Mix the sugar and eggs for 3 minutes. Add hazelnuts and stir for another 2 minutes. Add baking powder and stir briefly. Place in a springform pan lined with baking paper and bake at 150 ° C for 35 minutes. Bring the sour cherries to the boil with the vanilla pudding powder, spread thickened on the cooled cake base. Let cool down. Cover with whipped cream and decorate with chocolate flakes.