Frosted Chocolate Brownie Supreme

Ingredients

3/8 c sugar
8 egg whites
1/2 c nonfat sour cream
3/8 c evaporated skim milk
2 ts vanilla extract
1 3/8 c all purpose flour
1 t baking powder
1/2 ts salt
5/8 c unsweetened cocoa

Instructions

Vegetable cooking spray Creamy chocolate frosting