Table of Contents

Cocoa powder: For a truly deep, intense chocolate flavor and a rich, dark hue in your brownie layer, we highly recommend using dark unsweetened cocoa powder (often labeled as Dutch-processed cocoa). This type of cocoa has a lower acidity and a more pronounced, less bitter chocolate taste, contributing significantly to the signature fudginess and depth of flavor in the brownie portion. However, if you only have regular unsweetened cocoa powder on hand, you can certainly substitute it; just be aware that the brownies might be slightly lighter in color and have a subtly different, perhaps sharper, flavor profile. The key is to always use unsweetened cocoa, as sweetened versions will throw off the carefully balanced sugar content in the recipe.

Brown sugar: Light brown sugar is specifically called for in the blondie batter for this recipe, and it plays a crucial role in both flavor and texture. Its natural molasses content adds essential moisture and a delightful, subtle caramel flavor that truly distinguishes the blondie layer from the brownie layer. This contrast in sweetness and depth of flavor is what makes brownie blondies so uniquely special and appealing. While you *can* use dark brown sugar as a substitute, it will impart a more intense molasses flavor and potentially a chewier, denser texture, which might lessen the distinct, bright contrast between the two layers. For the intended balance and signature blondie taste, stick to light brown sugar.

Egg: You’ll notice this recipe cleverly calls for both whole eggs and an extra egg yolk. This isn’t a mistake; it’s a critical secret to achieving that coveted, ultra-chewy and rich texture! The whole eggs provide vital structure and moisture to the bars, while the additional egg yolk is the magic ingredient responsible for making them incredibly rich, dense, and wonderfully chewy. Egg yolks are primarily composed of fat, which contributes directly to the fudginess and helps prevent a dry, cakey texture. Always ensure your eggs are at room temperature, as this helps them emulsify better with the other ingredients, leading to a smoother, more uniform batter and a consistently baked product.

Chocolate chips: The quality and type of your chocolate chips significantly impact the final taste and texture of your brownie blondies. For the best, most balanced flavor that complements both the brownie and blondie layers without being overly sugary, we highly recommend using semi-sweet or dark chocolate chips. These varieties offer a pleasant bitterness that cuts through the sweetness. Brands like Ghirardelli or Guittard are excellent choices due to their superior melting qualities and rich cocoa flavor, which create luscious pockets of molten chocolate. Avoid milk chocolate chips, as they can be too sweet and don’t provide the same depth of flavor needed here.

Chopped chocolate bar: While chocolate chips are perfectly acceptable and delicious, incorporating a chopped chocolate bar (especially a good quality dark chocolate) brings an elevated, artisanal touch to these bars. When a chopped chocolate bar melts, it creates more luscious, irregular, and often larger pockets of pure melted chocolate throughout the bars, enhancing the gooey factor and providing a more gourmet look and feel. The uneven pieces also contribute to a varied texture. If you don’t have a chocolate bar on hand, feel free to use regular chocolate chips instead; the results will still be delicious, but the texture of the melted chocolate pockets will be slightly more uniform.

Always ensure all your cold ingredients, most notably eggs and butter, are brought to room temperature before you begin the mixing process. This allows them to incorporate more smoothly and evenly into the batter, preventing any curdling or separation, and ultimately ensuring a consistent, beautifully baked product. Full ingredient measurements and comprehensive, detailed instructions can be found in the easy-to-follow recipe card below!

Embark on your journey to create these spectacular brownie blondies! While a stand mixer is completely unnecessary, you’ll need two separate mixing bowls (one medium, one small) and a reliable whisk. Before you begin mixing any ingredients, it’s crucial to prepare your baking vessel: thoroughly line a square 8×8 inch baking pan with parchment paper, ensuring it overhangs generously on all four sides to create convenient “slings” for effortless removal later. This prevents sticking and makes post-baking cleanup a breeze. Finally, preheat your oven to a steady 350 F (180 C) to ensure it’s perfectly ready when your batters are.

For the Blondie Batter: Sweet and Chewy Perfection

STEP 1: Whip up the Wet Ingredients. In your medium mixing bowl, combine the light brown sugar, granulated sugar, the whole large egg, the extra large egg yolk, and the vanilla extract. Vigorously whisk these ingredients together by hand for about 1 full minute. You’re looking for the mixture to become noticeably lighter in color, slightly thickened, and delightfully fluffy. This crucial aeration step introduces air into the batter, which is key for achieving the blondie’s signature chewy, tender texture and a slightly crackly top (image 1 below).

Next, carefully and steadily stream the hot melted unsalted butter into this aerated egg and sugar mixture. It’s absolutely essential to whisk continuously and vigorously as you pour. This rapid whisking prevents the eggs from scrambling due to the heat of the butter and ensures that the butter is fully incorporated and emulsified into the batter, creating a smooth, glossy, and cohesive base for your blondies.

STEP 2: Incorporate the Dry Ingredients and Prep for Layering. Into your prepared blondie wet mixture, gently fold in the all-purpose flour, baking powder, salt, and your chosen chopped dark chocolate (or high-quality chocolate chips). Use a rubber spatula for this step, and mix only until the dry ingredients are *just* combined and no visible streaks of flour remain. Be cautious not to overmix the flour, as this can excessively develop gluten, leading to a tough, rather than tender and chewy, blondie. Once thoroughly mixed, spread about two-thirds of this delicious blondie batter evenly into your parchment-lined baking pan, using an offset spatula for smooth distribution. Reserve the remaining one-third (approximately 2/3 cup) of the blondie batter; this will be used for dolloping on top later to create that visually appealing and texturally interesting marbled effect (image 2 below). Set both the prepared pan and the reserved batter aside for now.

Creating the Rich Brownie Batter

STEP 3: Assemble the Brownie Batter. In a separate, smaller mixing bowl, whisk together the granulated sugar, the remaining whole large egg, and vanilla extract until the mixture is light and fluffy, similar to the initial blondie base. This aeration helps to create that desired fudgy texture with a slight chew. In a small, microwave-safe bowl (heating in 30-second intervals, stirring between each) or a double boiler, gently melt together the semi-sweet chocolate chips and the unsalted butter until the mixture is completely smooth and glossy. Once melted, carefully stream this warm chocolate-butter mixture into your egg and sugar blend, whisking constantly to ensure everything is thoroughly combined and perfectly emulsified. Finally, gently fold in the all-purpose flour, dark unsweetened cocoa powder, salt, and the remaining 1/4 cup of chopped dark chocolate using a rubber spatula. Again, mix just until the dry ingredients are fully incorporated and no dry pockets are visible, but be careful not to overmix, as this can lead to a tougher brownie (image 3 above).

Layering and Swirling for a Stunning Finish

STEP 4: Layer the Brownie Goodness. With an offset spatula or the back of a spoon, carefully and evenly spread the freshly made brownie batter directly on top of the blondie batter layer that you’ve already placed in your baking pan. Take your time to spread it gently from edge to edge, ensuring a smooth, uniform chocolate layer without disturbing the blondie layer underneath. This creates a distinct, beautiful division between the two flavors and textures (image 4 above).

STEP 5: Add the Reserved Blondie Batter. Now it’s time to add a decorative and flavorful touch that will create a stunning marbled effect. Using a small spoon or a cookie scoop, dollop the reserved blondie batter in tablespoon-sized balls over the top of the brownie layer. Aim for an even distribution across the entire surface of the pan; these pockets of blondie will create beautiful streaks, add contrasting color, and contribute additional chewiness to the final bars (image 5 above).

STEP 6: Swirl to Perfection and Bake! Take a skewer, a toothpick, or even the tip of a butter knife and gently swirl the two batters together. Make elegant S-shapes or figure-eights, carefully pulling the brownie up into the blondie and vice-versa. Remember, the key here is to create a lovely marbled appearance without over-swirling. Excessive swirling will cause the batters to fully combine, and you’ll unfortunately lose that distinct, appealing two-tone look and marbling (image 6 below). For an extra touch of decadence and visual appeal, sprinkle more chopped dark chocolate over the swirled surface. Finally, carefully place your pan into the preheated oven and bake for approximately 25-26 minutes. The brownie blondies are ready when the top of the blondie layer appears golden brown and shiny, and a toothpick inserted into the center comes out with moist crumbs or a slight smear of melted chocolate, but not wet batter. Overbaking will result in dry bars, so keep a close eye and trust the toothpick test!

Determining the perfect doneness for fudgy bars can be tricky, as they continue to set outside the oven. Here’s the key: the top of the blondie batter should appear golden brown and slightly shiny around the edges, while the center may still look a tiny bit underbaked. For a definitive test, gently insert a toothpick or a thin skewer into the very center of the pan. If the toothpick comes out with moist crumbs clinging to it or a delightful smear of melted chocolate, your brownie blondies are perfectly done! If it comes out completely clean, they are likely overbaked and will be drier. Remember, these bars will continue to cook slightly from residual heat as they cool outside the oven, so it’s always better to err on the side of slightly underbaked for maximum fudginess.

Absolutely! If you’re looking to feed a crowd or simply want more of these amazing bars, you can certainly bake this recipe in a 9×13 inch pan. However, to ensure they aren’t too thin and maintain their ideal fudgy-gooey texture and proper height, we highly recommend making a double batch of the recipe. This will provide sufficient volume for satisfying, thick bars. Keep in mind that a larger, thicker batch will inherently require a longer baking time. Start checking for doneness around the 30-minute mark, and then continue baking in 5-minute increments until the toothpick test yields the desired results (moist crumbs or a melted chocolate smear, not wet batter).

While I haven’t personally tested this specific brownie blondie recipe with gluten-free flour blends, many bar recipes adapt quite well to a good quality 1:1 gluten-free baking flour blend (one that typically contains xanthan gum for structure). If you decide to experiment with a gluten-free alternative, I would love to hear how they turn out! Please share your results and any tips in the comments section – it’s always exciting to learn about successful adaptations and help other bakers with dietary needs.

A sinking middle, especially while cooling, is a classic and common sign of underbaked bars. If a toothpick inserted into the center came out covered in thick, raw batter, it means the internal structure of the bars hadn’t fully set before being removed from the oven, leading to a collapse as the internal temperature dropped. To prevent this, ensure you’re baking until that toothpick test consistently shows moist crumbs or melted chocolate. Additionally, opening the oven door too frequently during baking or inconsistent oven temperatures can also contribute to this issue, so try to keep the oven door closed and use an oven thermometer if you suspect temperature fluctuations.

For those picture-perfect, clean slices that showcase the beautiful layers, patience is truly a virtue! Ensure your brownie blondies are completely cool – ideally, chilled in the refrigerator for at least 30 minutes (or even an hour) after they’ve reached room temperature. This chilling step allows the chocolate and sugars to firm up, making for much cleaner cuts. Use a large, sharp chef’s knife. For each cut, wipe the blade clean with a damp cloth or paper towel to prevent sticking and dragging crumbs through the bars. Slice straight down with a firm motion, rather than sawing. This method ensures smooth edges and stunning layers every time.

Discover More Irresistible Bar Recipes

If you’ve fallen in love with these layered brownie blondies, you’re in for an absolute treat! Our collection of bar recipes is brimming with other delectable options that are just as easy to make and equally satisfying. Perfect for sharing, parties, or simply indulging your sweet tooth, these versatile bars are sure to become new cherished favorites in your baking repertoire:

• Brown Butter Chocolate Chip Blondies: Elevate the classic blondie to new heights with the rich, nutty, and complex flavor of brown butter, combined with an abundance of melty chocolate chips for an irresistible chew.
• Decadent Banana Pudding Brownies: Experience a delightful fusion of classic Southern banana pudding flavors expertly layered into a rich, fudgy brownie base, creating a truly unique dessert mashup.
• Irresistible Biscoff Cookie Butter Brownies: For those who adore the warm, spiced notes of speculoos, these brownies feature generous swirls of creamy Biscoff cookie butter throughout, offering an unforgettable and comforting treat.
• Rich Brown Butter Espresso Brownies: Deep, intense chocolate notes are dramatically enhanced by the sophisticated, caramelized flavors of brown butter and a subtle, aromatic hint of espresso, creating a truly gourmet brownie.