1 Heat oven to 350°F (325°F for dark or nonstick pan). Grease bottom only of 9-inch square pan with cooking spray or shortening. (For easier cutting, line pan with foil, then grease foil on bottom only of pan.)
2 Make and bake brownies as directed on box. Cool completely.
3 Frost brownies with frosting. Sprinkle with peanuts; refrigerate while making cereal mixture.
4 Measure cereal into medium bowl; set aside. In 1-quart saucepan, melt peanut butter and chocolate chips over low heat, stirring constantly. Pour over cereal in bowl, stirring until evenly coated. Spread over frosted brownies. Refrigerate 1 hour or until set before cutting. For bars, cut into 4 rows by 4 rows. Store tightly covered at room temperature or in refrigerator.