Peppermint bark jigsawed over just-baked brownies results in a fudgy base topped with a ganache-like topping speckled with crackly minty candy bits. The brownie’s residual heat melts the dark chocolate bottom of the bark, fusing the two together as they cool. Costco’s big box of store-brand peppermint bark works best here, as it’s quite thin. Thicker options from other shops work too, but may pop off the brownie during slicing or eating.
Peppermint Bark Brownies
Heat the oven to 350 degrees. Lightly coat a half-sheet pan (17-by-13-by-1-inch) with nonstick cooking spray. Line the bottom and sides with parchment paper and spray the parchment.
Combine the chocolate chips and butter in a large sauce pot. Melt over medium-low heat, stirring occasionally to prevent scorching, until smooth. Remove the pot from the heat and let cool slightly. In a medium bowl, whisk together the sugar, flour, baking powder and salt.
Add the eggs to the melted chocolate one at a time, whisking well after each addition. Add the dry ingredients and stir with the whisk just until blended. Pour into the prepared pan and spread evenly.
Bake until a toothpick inserted 2 inches from the edge comes out clean, 20 to 22 minutes. Transfer to a wire rack. Let cool for 2 minutes, then gently lay the peppermint bark on top in a single layer. Cool completely in the pan on the rack. Use the parchment paper to slide the brownies out of the pan and cut into 2- to 3-inch squares.