1Heat oven to 350°F (325°F for dark or nonstick pan). In large bowl, stir together dry cake mix and butter. Press evenly in ungreased 13x9-inch pan.
2Using same bowl, stir frosting, milk, flour and egg until blended. Pour evenly over mixture in pan.
3Bake 43 to 47 minutes or until set. Serve warm or cool. Top each serving with remaining ingredients. Store covered in refrigerator.