A light lemon filling and topping grace this sponge cake to make a perfect springtime dessert. This cake takes extra time to prepare; however, if you love lemon you will find a reason to make this cake any time of year. This recipe uses a total of 10 eggs; all of the eggs whites are used, the yolk of 8 of the eggs are used, and the remaining yolk from 2 of the eggs can be discarded or used in other recipes.