Measure sugar, flour, soda, salt, baking powder, cocoa, margarine, buttermilk and vanilla into large mixer bowl. Beat at low speed to blend, then beat 2 minutes at medium speed. Add eggs; beat 2 minutes longer. Pour one-fourth of batter into each of four greased and wax paper-lined 8-inch layer cake pans; layers will be thin. Bake at 350~ about 15 minutes or until wooden pick inserted in center comes out clean. Two layers may stand while first two bake, if necessary. Cool slightly; remove from pans and continue cooling. Fill and frost layers with Sugarplum Chocolate Filling and Sugarplum Whipped Cream, alternately. Sugarplum Chocolate Filling. Combine chocolate and powdered sugar and water; blend. Add egg and beat well. Add margarine, one tablespoon at a time, beating thoroughly after each addition. Stir in almonds, reserving some for garnish. Sugarplum Whipped Cream. Whip cream with sugar and almond extract. ----