Adapted from Hershey’s recipe Thick and Fudgey Brownies with Hershey’s Mini Kisses Milk Chocolate.
Heat oven to 350°F, or 325°F for glass baking dish. Spray 9 x 9 x 2-inch baking pan with baking spray.
Stir together flour, cocoa, baking powder, and salt. Whisk together butter, sugar, and vanilla in large bowl. Add eggs; stir until blended. Stir in flour mixture. Spread batter in prepared pan. Place 9 peanut butter cups on batter; press gently until the batter starts to cover candy.
Bake 30 to 35 minutes or until brownies begin to pull away from sides of the pan. Cool completely in pan on wire rack. Cut into 2-inch squares.