Makes 16 brownies
(1 stick) unsalted butter, plus more for the pan
all-purpose flour, spooned and leveled
unsweetened cocoa powder
semisweet chocolate, chopped
pure vanilla extract
chopped mini peanut butter cups (about 20)
- Heat oven to 350° F. Butter an 8-inch square baking pan. Line with 2 crisscrossed pieces of parchment, buttering in between and leaving an overhang on all sides; butter the top piece of parchment.
- In a medium bowl, whisk together the flour, cocoa, baking powder, and salt; set aside.
- In a large microwave-safe bowl, combine the butter and chocolate. Microwave on high in 30-second intervals, stirring between each, until melted and smooth. Let cool slightly. Whisk in the sugar, eggs, and vanilla until smooth.
- Add the flour mixture and mix until just combined (do not overmix). Fold in the peanut butter cups.
- Spread the batter in the prepared pan and bake until a toothpick inserted in the center comes out clean, 30 to 35 minutes. Let cool completely in the pan.
- Holding the paper overhang, lift the brownies out of the pan and transfer to a cutting board. Cut into 16 squares (4 rows by 4 rows).