For the hazelnut cake, separate the eggs. Beat the egg whites until stiff. Beat the yolks, powdered sugar and vanilla sugar until foamy.
Mix in hazelnuts and baking powder. Finally, fold in the beaten egg whites. Pour the batter into a greased cake tin and bake at 180 degrees for approx. 45 – 50 minutes (test with a needle).
After cooling, cut the cake once and fill with jam and whipped cream. Sugar the hazelnut cake with powdered sugar.