Mix butter or margarine, 200 g sugar and egg yolks until frothy. Mix flour with baking powder and stir into the egg yolk mixture. Spread the dough on a greased baking sheet.
Beat 10 egg whites until stiff and pour in 200 g of sugar. Carefully fold in the hazelnuts and chocolate flakes. Put on the dough mass and distribute.
Bake in a preheated oven at 160 ° C for about 20 minutes.
Tip: Brush with chocolate icing or icing sugar rum icing.