Beat eggs, vanilla sugar and sugar until creamy until a thick, light cream is formed. Stir in the cooled butter.
Mix the hazelnuts with the pudding powder, flour and baking powder and gradually stir into the custard.
Pour the dough into a well-greased and floured ring cake pan and bake at 160 ° C for about 40 minutes. Please also do the chopstick test before removing it!