Mix the soft butter with sugar, marzipan and yolk until creamy, stir in the flour mixed with baking powder and the other ingredients and finally fold in the egg whites - put the dough in a prepared form, well greased and sprinkled with sugar, spread and place in the preheated oven at 160 ° for approx. Bake for 45 - 50 minutes. (Chopsticks sample) - when cold, sprinkle with icing sugar.