Whip snow and gradually add sugar, flour and lemon peel. All stir well and pour into a baking dish, covered with paper. Bake in a moderate oven. For the cream milk is boiled with flour, stirring constantly. The butter mix with sugar until blanching and added to it a little bit of cold milk mixture. Mix everything well. The cake is cut horizontally in two equal layers that are smeared with cream. Top and sides of the cake also smeared with cream. Garnish optional.