Skip to main content

Peanut Butter Swirl Brownies

Dollops of peanut butter filling are spooned onto brownie batter; pulling a knife back and forth through both results in a marbleized look.

Recipe information

  • Yield

    makes 9 large or 16 small

Ingredients

for the batter

1/2 cup (1 stick) unsalted butter, cut into small pieces, plus more for pan
2 ounces unsweetened chocolate, coarsely chopped
4 ounces semisweet chocolate, coarsely chopped
2/3 cup all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon coarse salt
3/4 cup granulated sugar
3 large eggs
2 teaspoons pure vanilla extract

for the filling

4 tablespoons (1/2 stick) unsalted butter, melted
1/2 cup confectioners’ sugar
3/4 cup smooth peanut butter
1/4 teaspoon coarse salt
1/2 teaspoon pure vanilla extract

Preparation

  1. Step 1

    Preheat oven to 325°F. Butter an 8-inch square baking pan and line with parchment, allowing a 2-inch overhang. Butter lining (not overhang).

    Step 2

    Make batter: Put butter and chocolates in a heatproof medium bowl set over a pan of simmering water; stir until melted. Let cool slightly. Whisk together flour, baking powder, and salt in a bowl.

    Step 3

    Whisk granulated sugar into chocolate mixture. Add eggs, and whisk until mixture is smooth. Stir in vanilla. Add flour mixture; stir until well combined.

    Step 4

    Make filling: Stir together butter, confectioners’ sugar, peanut butter, salt, and vanilla in a bowl until smooth.

    Step 5

    Pour one-third of batter into prepared pan; spread evenly with a rubber spatula. Drop dollops of peanut butter filling (about 1 tablespoon each) on top of batter, spacing about 1 inch apart. Drizzle remaining batter on top, and gently spread to fill pan. Drop dollops of remaining peanut butter mixture on top. Gently swirl peanut butter filling into batter with a butter knife, running the knife lengthwise and crosswise through layers.

    Step 6

    Bake until a cake tester inserted into brownies (avoid center and edges) comes out with a few crumbs but is not wet, about 45 minutes. Let cool slightly in pan, about 15 minutes. Lift out; let cool completely on a wire rack before cutting into squares. Brownies can be stored in an airtight container at room temperature up to 3 days.

  2. HOW TO MARBLEIZE BROWNIES

    Step 7

    Use two large spoons to drop dollops of filling over a base of chocolate batter. Add more batter on top, then more dollops of filling. Drag a butter knife back and forth with the tip touching the bottom of the pan.

Martha Stewart's Cookies
Read More
Like spicy carrot rigatoni and weeknight-fancy ravioli with peas.
Like lemony baked salmon and strawberry shortcake roll.
Turn humble onions into this thrifty yet luxe pasta dinner.
This one-pot dinner cooks chicken thighs directly on top of a bed of flavorful cilantro rice studded with black beans for a complete dinner.
Keep this easy frittata recipe on hand for quick breakfasts, impressive brunches, and fridge clean-out meals.
A warmly spiced Ashkenazi charoset, perfect for your Passover seder—or spooned over yogurt the next morning.
Crispy, Parmesan-crusted cutlets make this spring dish sing.
A feel-good dinner designed to cram a ton of veg in each serving.