How to Make It
Beat margarine at medium speed of an electric mixer until creamy; add 1 1/2 cups sugar, beating until fluffy. Add egg whites and egg, one at a time, beating after each addition. Combine buttermilk and water. Combine flour and next 3 ingredients; add to margarine mixture alternately with buttermilk mixture. Mix after each addition.
Pour batter into 2 (8-inch) round cakepans coated with cooking spray. Bake at 350° for 22 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire racks 10 minutes; remove from pans. Let cool.
Stir raspberry spread well. Slice each cake layer in half horizontally. Place 1 layer on plate; spread with 1/4 cup raspberry spread. Repeat with next 2 layers; top with fourth layer. Cover and chill.
Combine remaining 1/2 cup sugar, 2/3 cup cocoa, and cornstarch in top of a double boiler. Stir in milk. Bring water to a boil. Reduce heat to low; cook, stirring constantly, 18 minutes or until of spreading consistency. Stir in vanilla. Cover and chill. Spread on top and sides of cake. If desired, garnish with raspberries and mint sprigs.
Light and Luscious