When party guests want something sweet, it's hard to top a brownie made with HERSHEY'S Cocoa. As they bite into the moist square, they'll experience the crunch of REESE'S PIECES Minis. Then after another nibble, partygoers will find chocolatey chunks of HERSHEY'S Milk Chocolate Bars.
Heat convection oven to 300°F (standard oven: 350°F). Lightly spray one 18x26-inch full sheet pan with vegetable cooking spray. Place parchment paper on prepared sheet pan.
Blend together flour, HERSHEY'S Cocoa, baking powder and salt in large bowl. Set aside. Mix together melted butter, sugar and vanilla in 20 qt. bowl of mixer fitted with paddle attachment until creamy. Add eggs, mixing until fully incorporated. Gradually add flour mixture, mixing until well blended. Stir in REESE'S PIECES Minis and Chopped HERSHEY'S Milk Chocolate Bars. Spread batter in prepared pan.
Bake 30 to 40 minutes* or until brownie begins to pull away from sides of pan. Cool completely in pan on wire rack. Cut into 2-inch squares.
*If using convection oven, rotate pan one-half turn (180°) after 15 minutes of baking.