Why pick between brownies and blondies when you can enjoy both? These Fudgy Swirled Brownie Blondies combine the dense, caramel-vanilla flavor of blondies with the rich, chocolatey goodness of brownies in every bite.
If you’ve ever been torn between blondies and brownies, this recipe is the perfect compromise. It starts with a single base batter that’s divided: one half becomes a blondie with cornstarch for texture, and the other half becomes a chocolate brownie with unsweetened cocoa powder and chocolate chips. The result is a stunning, marbled bar that’s both fudgy and chewy.
Brownies vs. Blondies
The primary difference between brownies and blondies is cocoa powder. Brownies contain cocoa (and often chocolate chips), while blondies do not. Blondies emphasize caramel and vanilla notes and can feature white chocolate chips, though darker chocolate is uncommon.
Both treats share similar textures—fudgy, chewy, gooey, or cake-like—depending on the recipe. These swirled bars land between fudgy and chewy, giving you a substantial, satisfying bite each time.
Brownie Blondie Swirl — Ingredient Highlights
Use unsalted butter so you can control the salt level, or substitute salted butter and omit the added salt. Make sure the butter is softened before creaming. Choose unsweetened cocoa powder for the brownie portion; dark cocoa will deliver more intense chocolate flavor. Dark or semi-sweet chocolate chips are recommended for the brownie side.
Brownie Blondie Swirl — Tips and Tricks
How to Make Half Brownie, Half Blondie
Creaming the butter with both brown and granulated sugar aerates the mixture, creating small air pockets that help produce a soft, chewy texture. Use a hand mixer on high to get a smooth, evenly creamed mixture, then add eggs and vanilla.
Add flour and salt and mix until combined, using a spatula to scrape down the sides of the bowl. The batter will be thick. Scoop roughly 1 1/2 cups of batter into a separate bowl so you have two approximately equal portions.
To one bowl add the cocoa powder and chocolate chips to make the brownie batter; to the other add cornstarch to make the blondie batter. Mix the blondie batter first to avoid transferring any chocolate, ensuring there are no lumps of cornstarch. Then mix the brownie batter thoroughly so cocoa powder is fully incorporated.
Line or grease a 9 x 9-inch square pan. Spread the blondie batter in first, smoothing with a spatula. Drop spoonfuls of the brownie batter on top and use a spatula or a scoop to spread and swirl the batters into a marbled pattern.
Storing Your Brownie Blondies
Store the bars in an airtight container at room temperature for 3–4 days. For longer storage, freeze them in an airtight container for up to 4 months. Thaw at room temperature before serving.
Fudgy Swirled Brownie Blondies
Marley Goldin
Equipment
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Hand Mixer
Ingredients
- 1 cup unsalted butter (1 cup usually = 2 sticks)
- 1 cup brown sugar
- ½ cup granulated sugar
- 3 large eggs
- 2 teaspoons vanilla extract
- 1 ½ cup all-purpose flour
- ¼ teaspoon salt
- 1 tablespoon cornstarch
- ½ cup unsweetened cocoa powder
- ½ cup chocolate chips (dark or semi-sweet)
Instructions
- Preheat your oven to 350°F and line or spray a 9 x 9-inch square pan.
- In a large mixing bowl, cream together butter and both sugars with a hand mixer on high until smooth.
- Add vanilla extract and eggs and mix until combined.
- Add flour and salt and mix until well combined; the batter should be thick.
- Scoop about 1 ½ cups of batter into a separate bowl so you have two roughly equal portions. Add cocoa powder and chocolate chips to one bowl for the brownie batter, and add cornstarch to the other for the blondie batter. Mix the blondie batter first, then the brownie batter, ensuring no lumps remain.
- Spread the blondie batter into the prepared pan, then drop spoonfuls of the brownie batter on top. Smooth and swirl the batters together to create a marbled effect.
- Bake for 25–30 minutes, or until a toothpick comes out clean. Cool before slicing.
Pro Tips
- To quickly soften butter, microwave it in 15-second intervals until you can press an imprint with your finger.
- Be sure there are no clumps of cornstarch or cocoa powder—those pockets can taste bitter.