How to make
Beat the butter until fluffy with 1 cup powdered sugar. Gradually add the egg yolks, milk, sifted flour and baking powder. Finally, add the vanilla and the egg whites beaten with 1/2 cup powdered sugar.
Mix them carefully with a spatula. Pour the mixture into a cake form, covered with greased baking paper. Distribute a mixture of grated apples, breadcrumbs, walnuts and cinnamon on top.
Bake the cake in a preheated oven at low heat.