A piece of this light and airy cake is perfect for an afternoon pick-me-up spread with some fruity jam. Combine egg yolks with sugar, add flour and cornstarch, then carefully add the egg whites that have been beaten into soft peaks. Pour into a cake mold, and bake for 25 minutes at 350 °F. Once it's cooled, cut the cake in half and slather on as much jelly as you please before putting it back together.