Separate eggs. Whip the whipped cream until semi-stiff, stir in the sugar and vanilla sugar. Stir in the yolks, fold in the flour and baking powder, add the milk.
Beat egg whites into snow and fold into the mixture. Mix one third of the mixture with Nutella.
Grease a ring cake tin with butter and sprinkle with flour. Pour in the Nutella mixture first, then the rest of the batter.