Beat egg whites into snow, stir butter, powdered sugar, vanilla sugar and egg yolk until creamy. Mix flour with baking powder, stir in with eggnog, then fold in egg whites. Pour the dough into a 28 cm form, cover with the drained apricots. Make crumbles from 150 grams of flour, 120 grams of butter and 100 grams of sugar and place on top of the apricots.