Beat the eggs, powdered sugar and vanilla sugar until fluffy. Sift the flour and baking powder and gently fold in. Pour into a well greased and floured springform pan and bake in the oven (hot air) at 180° for about 30 minutes.
Allow to cool.
In the meantime, make a chocolate glaze.
Cut the cake apart and fill with jam or cream as desired. Then spread the cake thinly with jam and cover with the chocolate glaze.
Let chocolate dry and then decorate with sugar snow or food coloring as desired.