Irresistible Blueberry Blondies: Chewy Bars with Homemade Jam & Crumb Topping
Get ready for a truly delightful summer treat! These blueberry blondies are far more than just a simple dessert. They boast a perfectly chewy blondie base, generously layered with luscious, vibrant homemade blueberry jam, and crowned with a buttery, sweet crumb topping that evokes the comforting taste of a classic blueberry crumble. Imagine all the best parts of a brownie, but infused with the bright, fruity essence of blueberries – that’s what these bars deliver. This recipe transforms a classic bakery favorite into an accessible, show-stopping dessert for your home kitchen.
As a former pastry chef, I fondly recall blueberry blondies being a beloved staple in the bakery. My unique take on this classic, much like my blueberry crumb cake, replaces fresh blueberries with a rich, homemade blueberry jam. This innovative approach ensures that every bite is bursting with an incredibly intense, concentrated blueberry flavor that truly sets these bars apart, making them a standout dessert that’s sure to impress.
These blueberry blondies share the wonderfully fudgy and delightfully chewy texture reminiscent of classic brownies, but without any chocolate. This makes them an effortlessly perfect dessert for any summer gathering, picnic, or simply a sweet afternoon treat. They are easy to prepare, using everyday pantry ingredients, and promise a rewarding baking experience for both novice and experienced bakers alike. Dive into the world of blueberry bliss with this simple yet sophisticated recipe!
Table of Contents
What Are Blueberry Blondies, Exactly?
Blueberry Blondies are a delightful twist on the classic blondie bar. While traditional blondies are often considered a “brownie without chocolate,” featuring a rich, buttery, and vanilla-infused base, blueberry blondies take this concept to a new level by incorporating the sweet and tart flavors of blueberries. In this particular recipe, we elevate the blueberry experience even further by using a homemade jam and a delicious crumble topping, creating a truly unique and satisfying dessert bar.
- Fruity Brownie-Like Bars: They are similar to brownies in their dense, chewy, and moist consistency, but they forgo the chocolate for a brighter, fruitier profile. This makes them a fantastic alternative for those who love the texture of brownies but prefer a fruit-forward dessert.
- Effortlessly Easy to Make: You won’t need a stand mixer or any complicated techniques for these blondies. With just a few staple pantry ingredients and a whisk, these bars come together quickly, making them a perfect, low-stress baking project even for busy schedules.
- Packed with Intense Blueberry Flavor: Our secret weapon is the rich, homemade blueberry jam, similar to what you’d find in my wild blueberry scones. This method saturates every bite with a deep, concentrated blueberry taste that surpasses using fresh berries alone.
- Perfect for Any Occasion: These versatile bars are ideal for any time of year! Whether you’re making them for a summer picnic, a holiday gathering, or a cozy evening at home, they are always a crowd-pleaser. They also make excellent treats for lunchboxes or a thoughtful gift.
Why You’ll Love These Blueberry Blondies
There are countless reasons why these blueberry blondies are destined to become a beloved recipe in your collection. Here are just a few compelling factors that make them truly irresistible:
- Unforgettable Chewy & Fudgy Texture: The blondie base is meticulously crafted to deliver that perfect “chewy on the edges, fudgy in the middle” experience that distinguishes an exceptional bar cookie. The combination of brown sugar and an extra egg yolk creates a dense, moist, and delightfully rich texture that melts in your mouth.
- Intense, Concentrated Blueberry Taste: Forget bland, sparse berries! By incorporating a thick, homemade blueberry jam, we infuse every single bite with an authentic, deep, and vibrant blueberry flavor. This jam layer isn’t just a topping; it’s the heart of their bright, fruity appeal.
- Crunchy, Buttery Crumb Topping: The crumb topping is more than just an accent; it’s a star component. It adds a delightful textural contrast with its buttery, slightly crisp nature, reminiscent of the best fruit crumbles. This golden, sweet streusel takes the entire dessert to an elevated level of indulgence.
- Simple, No-Fuss Baking: This recipe is designed with ease in mind. You won’t need any complex techniques or specialized equipment. A whisk and a couple of bowls are all you require, making these blondies accessible and enjoyable for bakers of all skill levels, from beginners to seasoned pros.
- Perfect for Any Occasion: From casual family desserts to impressive potluck contributions or special celebrations, these blueberry blondies are always a guaranteed hit. Their cheerful appearance and universally loved fruit-and-crumble flavors make them suitable for any gathering, big or small.
- Made with Accessible Pantry Staples: You likely already have most of the ingredients on hand in your kitchen. This means that a batch of these delicious and satisfying blondies is just a quick whisk and a bake away, without the need for a special trip to the grocery store.
Key Ingredients and Smart Substitutions
Crafting the perfect blueberry blondie relies on a few essential ingredients, each playing a crucial role in achieving the desired texture and flavor. Here’s a closer look at what you’ll need and how each component contributes to the final delicious result, along with possible substitutions to help you bake with confidence.
Wild Maine Blueberries: These small, intensely flavored berries were my go-to almost exclusively during my time as a pastry chef, essential for recipes like my bakery-style blueberry muffins and blueberry rolls. Their concentrated flavor and smaller size make them ideal for jams and baked goods, and they are conveniently available year-round in the frozen section. For this recipe, frozen berries are actually preferred as they break down beautifully to create a smooth, rich jam. You can substitute with fresh blueberries or regular frozen blueberries, but be aware that the jam might have a slightly less intense blueberry flavor.
Brown Sugar: This isn’t just for sweetness; brown sugar is crucial for giving the blondie batter its signature chewy texture and a wonderful, deep caramelized flavor. The molasses content in brown sugar contributes significantly to a moister, softer blondie. You can use either light brown sugar or dark brown sugar, with dark brown sugar imparting a more pronounced molasses note and richer color.
Cornstarch: This ingredient is absolutely vital for achieving a super-thick, stable blueberry jam that won’t ooze out of your blondies during or after baking, ensuring a clean and delicious slice every time. It acts as a thickening agent, helping to bind the fruit juices into a beautiful, spreadable consistency. Do not substitute or omit it, or your blueberry jam will be too thin and could potentially make your blondies soggy and hard to handle.
Eggs: The recipe specifically calls for one whole large egg and one extra large egg yolk. The whole egg provides essential structure and moisture to the blondie, while the additional egg yolk is a secret weapon for achieving that coveted fudgy, dense, and ultra-chewy texture. The extra fat from the yolk contributes to a richer mouthfeel and helps prevent the bars from becoming too cakey, a technique also employed in my strawberry lemon blondies.
Unsalted Butter: Used melted in both the blondie batter and the crumb topping. Melted butter is key to creating that dense, chewy blondie texture, as well as helping to form the perfect, crisp crumbs for the topping. Using unsalted butter gives you precise control over the overall salt content in the recipe.
All-Purpose Flour: This is the primary structural component of both the blondie base and the crumb topping. Proper measurement is essential (see our tips below for accuracy) to achieve the ideal tender crumb in the blondie and the right consistency for the streusel.
Granulated Sugar: Used in both the jam and the crumb topping for balanced sweetness and to aid in the beautiful caramelization of the topping as it bakes.
Lemon Juice & Zest: These elements are crucial in the jam for adding a bright, zesty counterpoint to the sweetness of the blueberries. The citrus notes enhance the overall fruit flavor, making it pop and creating a more complex taste profile.
Vanilla Extract: A cornerstone in most baked goods, pure vanilla extract enhances all the other flavors in the blondie batter, adding a warm, comforting, and inviting aroma that is synonymous with homemade treats.
Baking Powder & Salt: Baking powder provides a little lift to the blondie, contributing to its tender crumb without making it overly airy. Fine sea salt, on the other hand, is essential for balancing the sweetness and expertly bringing out all the delicious flavors of the blueberries and butter.
You’ll find all precise ingredient measurements and comprehensive, step-by-step instructions thoughtfully laid out in the complete recipe card below!
Fruity Variations for Your Blondies
While blueberry blondies are undeniably delicious and a crowd-pleaser, the beauty of this recipe lies in its incredible versatility. The structure of the blondie base and crumb topping allows for wonderful adaptability with other fruits, inviting you to experiment and customize your bars to suit your preferences or what’s in season. Don’t hesitate to get creative!
Feel free to substitute the blueberries for an equal amount of other berries or even a delightful combination. Here are some fantastic alternatives to consider for crafting your homemade jam layer, each bringing its unique flavor profile:
- Strawberries: Dice fresh or frozen strawberries and cook them down for a beautifully sweet, classic summery jam. Their natural sweetness pairs wonderfully with the rich blondie base.
- Raspberries: Opt for raspberries to create a jam that is exquisitely tart and incredibly aromatic. For a smoother texture, you might want to press the cooked jam through a sieve to remove some of the seeds.
- Blackberries: These offer a deeper, more earthy, and slightly tart berry flavor, making for a richer and more complex jam filling. Blackberries also provide a stunning deep purple hue to your blondies.
- Mixed Berries: For a wonderfully complex and vibrant flavor experience, try a combination of strawberries, raspberries, and blueberries. This medley ensures a multifaceted fruitiness in every bite.
- Cherries: Pitted and chopped cherries (fresh or frozen) can also make a truly delightful jam filling. They offer a bolder, slightly almond-like flavor that pairs surprisingly well with the blondie and crumb.
It’s important to note that depending on the natural water content and pectin levels of the specific berry you choose, you may need to adjust the amount of cornstarch slightly in your jam. Generally, softer berries like raspberries and strawberries, or those with higher water content, might require a touch more cornstarch to reach that perfect thick, spreadable jam consistency. Firmer fruits will likely need less. Always aim for a jam that is thick enough to hold its shape when spread, as this is crucial for preventing it from making your blondies soggy or runny.
Step-by-Step Recipe Instructions
Baking these blueberry blondies is a straightforward and incredibly enjoyable process, yielding fantastic results every time. Follow these detailed, easy-to-understand steps to ensure you create perfectly chewy, jam-filled bars with a delightful crumb topping. For the best outcome, it’s always a good idea to read through the entire recipe card below before you begin!
Step 1: Prepare Your Pan and Oven. Begin by lining a metal 8×8 inch baking pan with parchment paper. Ensure you leave an overhang on two opposite sides; these will act as convenient “handles” for lifting the cooled blondie slab out later. Preheat your oven to the specified temperature of 350°F (180°C). Proper preheating is crucial for even baking and achieving that perfect golden-brown crust.
Step 2: Craft the Delicious Blueberry Jam. In a small saucepan, combine your frozen wild blueberries, granulated sugar, fresh lemon juice, and a touch of lemon zest. Cook this mixture over medium heat, stirring occasionally to prevent sticking and ensure even cooking. You’ll observe the berries beginning to release their vibrant juices and the mixture starting to bubble actively, typically taking about 8-9 minutes. While this is happening, whisk together the cornstarch and water in a small bowl to create a smooth slurry. Stir this slurry into the bubbling jam and continue to cook for another 2 minutes, stirring constantly, until the jam thickens considerably and is able to coat the back of a spoon. Once thickened, transfer this rich jam to a separate heatproof bowl and set it aside to cool completely to room temperature. Cooling is absolutely crucial here; if the jam is warm, it will melt into the blondie batter when layered, leading to a less defined and potentially soggy result.
Step 3: Assemble the Buttery Crumb Topping. In a medium-sized mixing bowl, combine the all-purpose flour, granulated sugar, light brown sugar, and melted unsalted butter. Use your fingertips or a fork to mix these ingredients until cohesive crumbs form. Some crumbs will be larger, some smaller – that’s precisely the rustic perfection we’re looking for! Chill this crumb topping in the fridge while you proceed with preparing the blondie batter. Chilling helps the butter firm up, ensuring a wonderfully crisp and distinct topping once baked. Before sprinkling, remember to break up any larger clumps that may have formed during chilling.
Step 4: Whisk Together the Wet Ingredients for the Blondie Batter. In a large mixing bowl, combine the light brown sugar, granulated sugar, the whole large egg, the extra large egg yolk, and vanilla extract. Whisk these ingredients vigorously for approximately 1 minute until the mixture becomes visibly lighter in color, thickens slightly, and appears fluffy. This aeration step incorporates air, which contributes to a tender and chewy blondie. Next, gradually stream in the hot melted butter while continuously whisking to emulsify it into the egg mixture. This continuous whisking is important to prevent the hot butter from scrambling the eggs and ensures a smooth, cohesive batter.
Step 5: Gently Fold in the Dry Ingredients. Add the measured all-purpose flour, baking powder, and fine sea salt to the wet ingredients in the bowl. Using a rubber spatula, gently fold these dry ingredients into the wet mixture until they are just combined and no streaks of dry flour remain. Be extremely careful not to overmix, as overworking the gluten in the flour can lead to tough, dense, and less desirable blondies. A light hand here ensures a wonderfully soft and chewy result.
Step 6: Spread the Blondie Batter. Carefully transfer the prepared blondie batter into your parchment-lined 8×8 inch baking pan. Use an offset spatula or the back of a spoon to gently and evenly spread the batter across the entire bottom surface of the pan, ensuring a consistent base for your layers.
Step 7: Layer with Blueberry Jam. Once the blondie batter is smoothly spread in the pan, carefully spoon the completely cooled blueberry jam over the top. Use an offset spatula or the back of a spoon to gently spread the jam evenly across the entire surface of the batter, making sure to reach close to the edges for a full-flavored experience in every bite.
Step 8: Add Crumb Topping and Bake. Evenly sprinkle the chilled crumb topping over the vibrant blueberry jam layer. For an extra pop of color and intensified blueberry goodness, you can scatter a few additional frozen wild blueberries on top of the crumb. Place the pan in your preheated oven and bake for approximately 28-30 minutes, or until the edges are beautifully golden brown, the center looks set and slightly puffy, and a toothpick inserted into the center (avoiding the jam layer, if possible) comes out with just a few moist crumbs attached. It’s crucial to avoid overbaking to maintain that signature fudgy and chewy texture.
Step 9: Cool Completely and Slice. This step is absolutely crucial for achieving clean, perfect blondie slices! Let the pan cool completely on a wire rack at room temperature. Rushing this process will result in messy, crumbly bars that are difficult to cut neatly. Once fully cool (which can take a couple of hours, so patience is key!), use the parchment paper overhang to gently lift the entire blondie slab out of the pan. Place it on a cutting board and use a sharp knife to slice it into your desired portions – typically 16 small bars for a crowd, or 9 larger, more generous squares for a heartier treat. Enjoy your magnificent homemade blueberry blondies!
If you’re as obsessed with berry-stuffed bars and crumb toppings as I am, you absolutely must try my jammy mixed berry crumb bars next. They’re another one of those treats that vanish from the pan far too quickly, especially if you share my love for a perfectly buttery, sweet crumble! These recipes prove that a good crumb topping can truly elevate any baked good.
Tips for Baking the Perfect Blondies
Achieving bakery-quality blueberry blondies at home is easier than you think, especially when armed with a few insider tips and tricks:
- Measure Dry Ingredients Accurately: This is arguably the most crucial baking tip for consistent results! Never scoop your measuring cup directly into the flour bag; this action compacts the flour, leading to too much being used and a dry, dense blondie. Instead, employ the “spoon-and-level” method: fluff the flour in its container, then spoon it into your measuring cup until overflowing, and finally, level it off with the back of a straight edge (like a knife). For the absolute best and most consistent results, invest in a kitchen scale and measure by weight.
- Don’t Overmix the Batter: Once you add the dry ingredients to the wet mixture, mix only until they are just combined. Overmixing develops the gluten in the flour, which can lead to tough, rubbery blondies that lack that desirable soft and chewy texture. A few streaks of flour disappearing are fine; stop mixing as soon as everything is incorporated.
- Ensure Jam is Fully Cooled: This cannot be stressed enough! Spreading warm jam onto your delicate blondie batter will cause it to melt and potentially sink into the batter, making it difficult to spread evenly and resulting in a less defined and possibly soggy layer. Allow the jam to cool completely to room temperature (or even chill it slightly in the fridge) for a distinct, stable, and beautiful layer.
- Chill the Crumb Topping: Just like the jam, chilling the crumb topping is a simple yet effective step. It helps the butter in the crumbs firm up, which prevents them from melting too quickly in the oven. This ensures you get those delightful, separate, and wonderfully crisp crumbs on top of your blondies.
- Cool Completely Before Slicing: This is a non-negotiable step for clean, beautiful slices. Blondies are incredibly soft and delicate when warm, and attempting to cut them prematurely will result in a crumbly, messy outcome. Patience is truly key here; allow them to cool for at least 2 hours, or even longer, before lifting and slicing.
- Use a Metal Baking Pan: For optimal baking, metal pans are highly recommended. They conduct heat more efficiently and evenly than glass or ceramic baking dishes. While glass or ceramic pans can be used, they often require longer baking times and might yield slightly different textures.
- Parchment Paper is Your Friend: Lining your pan with parchment paper is a small effort that pays off immensely. It not only prevents sticking but also creates convenient “handles” to easily lift the entire slab of cooled blondies out of the pan. This makes slicing them neat and effortless.
- Know Your Oven: Oven temperatures can vary significantly from one appliance to another. If your oven tends to run hot or cold, adjust the baking time accordingly. It’s always a good idea to keep an eye on the blondies, especially during the last 10 minutes of baking, looking for those golden-brown edges.
If you tried this delicious recipe or any other on my website, please let me know how it went in the comments section below; I absolutely love hearing from you and your baking experiences! Also, please take a moment to leave a star rating while you’re there to help other bakers discover this treat! You can also tag me on Instagram or Facebook so I can see your wonderful creations!
Blueberry Blondies Recipe Card
Blueberry Blondies
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Equipment
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square 8×8 baking pan
Ingredients
Blueberry Jam Filling
- 1 cup frozen wild Maine blueberries, see notes for substitutes
- 2 tablespoons granulated sugar
- 1 teaspoon lemon juice
- 1/4 teaspoon lemon zest
- 2 teaspoons water
- 2 teaspoons corn starch
Crumble
- 1/4 cup all-purpose flour, *See notes below for measuring*
- 1 tablespoon granulated sugar
- 1 tablespoon light brown sugar, packed
- 2 tablespoons unsalted butter, melted
Blondie Batter
- 2/3 cup light brown sugar, packed
- 1/4 cup granulated sugar
- 1 large whole egg
- 1 large egg yolk
- 1 teaspoon vanilla extract
- 1/2 cup unsalted butter, melted
- 1 cup + 2 tablespoons all-purpose flour, *See notes below for measuring*
- 1/2 teaspoons fine sea salt
- 1/4 teaspoon baking powder
- 1/4 cup frozen wild Maine blueberries, for topping
Instructions
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Line a metal square 8×8 baking pan with parchment paper and preheat the oven to 350 F/180 C.
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Cook the frozen blueberries, lemon zest, lemon juice, and sugar over medium heat for 8-9 minutes or until the berries start to release their juices and boil. Whisk together the cornstarch and water and stir it into the jam. Cook for 2 minutes longer until the jam is super thick. Transfer it to a bowl and set it aside to cool completely.1 cup (125 g) frozen wild Maine blueberries, 2 tablespoons (30 g) granulated sugar, 1 teaspoon lemon juice, 1/4 teaspoon lemon zest, 2 teaspoons water, 2 teaspoons corn starch
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In a medium bowl, combine the flour, sugar, brown sugar, and melted butter until crumbs form. Chill in the fridge until ready to use. Before using, break up the crumb into small pieces!1/4 cup (35 g) all-purpose flour, 1 tablespoon (15 g) granulated sugar, 1 tablespoon (15 g) light brown sugar, 2 tablespoons (28 g) unsalted butter
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In a large bowl, whisk together the brown sugar, granulated sugar, egg, egg yolk, and vanilla extract until light and fluffy, about 1 minute. Then whisk in the melted butter. Once combined, fold in the flour, baking powder, and salt.2/3 cup (126 g) light brown sugar, 1/4 cup (50 g) granulated sugar, 1 (55 g) large whole egg, 1 (17 g) large egg yolk, 1 teaspoon vanilla extract, 1/2 cup (113 g) unsalted butter, 1 cup + 2 tablespoons (142 g) all-purpose flour, 1/2 teaspoons fine sea salt, 1/4 teaspoon baking powder
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Evenly spread the batter into the prepared pan.
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Evenly spread the cooled blueberry jam over the top of the batter. Then sprinkle the crumb topping and extra blueberries over the top.1/4 cup (34 g) frozen wild Maine blueberries
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Bake for 28-30 minutes, or until the middle is puffy, the edges are golden brown, and a toothpick inserted into the center comes out covered with just a few moist crumbs.
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Let the pan cool completely on a wire rack. Then lift the parchment paper up to remove it from the pan. Use a sharp knife to cut it into 16 small bars or 9 large bars. Enjoy!
Notes
Metal baking pans are recommended: Ceramic or glass baking pans conduct heat differently and will require longer baking times.
Blueberry substitutions: This recipe is best with frozen blueberries! For the best blueberry flavor, I highly recommend using the wild Main berries. You can also substitute them for raspberries, blackberries, strawberries, or a mixture of berries!
Storage: Once cool, store them in an airtight container at room temperature for 3-4 days.
Freezing: Store the cut or uncut bars in an airtight container or freezer bag for up to 1 month.
The calorie information provided for the recipe is an estimate. The accuracy of the calories listed is not guaranteed.