Mix the flour and the cooled margarine, then add all the other ingredients. Then fold in the stiffly beaten egg whites. Spread the dough on a greased tray and bake until golden yellow at approx. 150 ° C.
For the topping, stir the egg yolks, vanilla sugar and powdered sugar until foamy and spread on the cake while it is still hot. It is best to let it dry overnight and then cut into diamonds.