Step 1

Heat oven to 350°F (325°F for dark or nonstick pan). Grease bottom of 9-inch square pan with shortening or cooking spray. Make brownie batter as directed on box. Stir in chocolate chips and 1/4 cup of the peanuts. Spread in pan.

Step 2

Bake 28 to 31 minutes or until toothpick inserted 2 inches from side of pan comes out almost clean. Cool completely on cooling rack, about 1 hour 30 minutes.

Step 3

In medium microwavable bowl, stir frosting and peanut butter until blended. Microwave frosting mixture uncovered on High 20 to 30 seconds or until mixture is warmed and pourable. Pour over baked brownie; spread over top. Sprinkle remaining peanuts on top. Let stand about 1 hour or until set.

Step 4

Cut into 4 rows by 4 rows. Store covered in airtight container.