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 20 cm layer cake pans; layers will be thin. Bake at 180ºC 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. ----