Marble Blondies Recipe

As someone who grew up in the Hannah Montana era, I’d be remiss to not make the joke that these blondies are truly “the best of both worlds.” This recipe uses one simple batter to yield a vanilla blondie and a chocolatey, brownie-esque batter that are layered and swirled to create mesmerizing, decadent marbled blondies. If you can’t decide between blondies and brownies, then this recipe is the answer.

White chocolate chips stud the caramel-y, vanilla blondie batter and semi-sweet chocolate chips stud the rich brownie batter, making for a stark, stunning contrast when baked and sliced. Both chewy around the edges and soft and fudgy in the center, these marble blondies have a little something for everyone. 

Blondies vs. Brownies

Blondies and brownies use many of the same ingredients, but their batters are very different. Blondie batters tend to use all brown sugar which provides moisture, a deep caramel flavor, and a fudgy center. Since this batter doubles as blondie and brownie, I use a combination of light brown sugar and a little granulated sugar to balance the flavor of the chocolate batter and help create a bit of that crinkly paper-thin top of a good brownie. 

To transform the blondie batter into chocolate, I add Dutch-process cocoa and melted chocolate plus an extra egg yolk and espresso powder. The extra egg yolk helps provide more fat to balance out the dry cocoa. Dutch-process cocoa provides deep color and rich flavor while the melted chocolate yields a fudgy texture. When baked together, the batters meld and yield a treat that’s truly marvelous.

Best of Both Worlds 

As an incredibly indecisive person, I almost always get twist ice cream when ordering soft serve. Consider these the “twist” of blondies. A not-too-sweet, vanilla blondie swirls with a decadent chocolate brownie to create a treat that’s the best of both worlds. 

With this recipe, you get a little of everything in each bite—caramel notes from the brown sugar, a sweet vanilla flavor, chocolatey decadence, creaminess from the melted chocolate, chewy edges, a fine and delicate crust, and a soft, fudgy center. The eye-catching marbled appearance will have people thinking you spent hours creating those playful swirls. 

Tips for the Perfect Marble Effect 

Swirling the batters can feel daunting, especially in a recipe like this where the batters are thicker than a cake batter. Here’s everything you need to know to create the most stunning marbled effect.

• Much of the heavy lifting in creating a marbled cross-section in the blondies is done by layering the batters in the pan. Essentially, you want to alternate dropping the batters in two layers to resemble a checkerboard. Doing this creates contrasting layers in the blondies that give a marbled appearance when sliced. Moreover, this also means you only have to worry about creating your swirls on the surface, rather than all the way through. 
• When swirling the batters, I’ve found the most success with the side of a small offset spatula or the spine of a butter knife rather than a toothpick. These tools are better able to drag the thick batters into one another. 
• Don’t worry about the texture on the surface that comes from swirling. It’ll mostly settle once baked.

Easy Variations

Want a little extra pizzazz? Consider this:

• Swap the white chocolate chips in the blondie batter for toasted nuts, such as pecans or walnuts.
• Swap in bittersweet chocolate for semi-sweet if you like a more intense, less sweet chocolate flavor. 
• Swirl a few tablespoons of your favorite nut butter or Nutella in addition to the brownie batter for a flavor-packed bite. 

How to Store Marble Blondies

These blondies are best the day of baking. Leftover blondies can be stored in an airtight container at room temperature for up to 4 days. 

Marble blondies can be tightly wrapped in plastic wrap then placed in an airtight container or resealable plastic bag and frozen for up to 2 months. Thaw at room temperature.

Blondies and Brownies Galore