1 cup butter or margarine
2-1/2 cups sifted Powdered Sugar
4 egg yolks
2 egg whites
1/2 cup semi-sweet chocolate pieces, melted
2 tablespoons creme de menthe
1 tablespoon egg white
1 10-inch angel food cake
Stir butter to soften; add sugar; cream until very light and fluffy. Add egg yolks, one at a time, and beat well. Set aside half of this mixture.
To first half, add 2 egg whites and partially-cooled melted chocolate; beat until light and fluffy.
To remaining half, add creme de menthe and 1 tablespoon egg white; beat until light and fluffy.
Cut cake into 5 layers. Spread bottom layer with chocolate filling; place second layer over filling and spread with mint filling. Repeat chocolate and mint layers; top with remaining layer and spread with chocolate filling. Refrigerate for several hours.