Peanut Butter Swirl Brownies

A layer of peanut butter sweetened with brown sugar tops these delightful brownies.

Serves: 16Hands-on: 30 minutesTotal: 2 hours 15 minutesDifficulty: Easy

Serves: 16


  • 8 oz. unsweetened chocolate, finely chopped
  • 1 1⁄2 cup butter, cut into 1⁄4-inch cubes
  • 2 cup plus 4 Tbsp. all-purpose flour, divided
  • 2 tsp. baking powder
  • 1⁄2 tsp. salt
  • 3 cups granulated sugar
  • 2 tsp. vanilla extract
  • 8 large eggs, room temperature, divided
  • 1 cup walnuts, toasted and chopped
  • 1 cup creamy peanut butter
  • 1⁄2 cup mascarpone cheese
  • 4 Tbsp. firmly packed light brown sugar


  • Preheat the oven to 325°F. Lightly coat the sides of a 9-by-13-inch baking dish with butter and flour. Line the bottom of the pan with parchment paper and butter the top of the parchment paper.
  • Melt the chocolate and butter in the top of a double boiler over hot (not boiling) water, stirring continuously. Remove from heat and set aside to cool for a few minutes. Whisk together 1 cup flour, baking powder, and salt. Set aside.
  • Blend the granulated sugar into the chocolate mixture, a little at a time. Add the vanilla. Stir 6 eggs into the mixture, one at a time. Fold the flour mixture into the chocolate mixture just until lightly blended. Gently fold in the walnuts. Set aside.
  • In a separate bowl, cream together the peanut butter, mascarpone cheese, remaining 2 tablespoons flour, and brown sugar. Beat the remaining egg into the mixture. Set aside.
  • Spread the batter into the prepared pan. Spoon the peanut butter mixture on top of the batter in 12 equal parts evenly spaced. Bake for 45 minutes. Remove the brownies from the oven, and place them on a cooling rack lined with parchment paper for at least 1 hour before cutting.