The classic sponge cake is ... all kinds of frostings and fillings, from fruit preserves ... the eggs alone. Cooks Tips: When beating egg whites, it is important to ... rum, if desired. Frost the outside. Alternatively, the cake ... use in assembled desserts.
Add salt to egg whites; beat with electric mixer ... each addition until frosting peaks. Fold in vanilla. Makes enough to frost 2 (9 inch) cake layers.