Beat eggs, powdered sugar and vanilla sugar until thick and frothy. Stir in eggnog and rapeseed oil. Fold in the flour, salt, baking powder and potato starch.
Pour two thirds of the mixture into a greased wreath cake tin sprinkled with nuts. Mix the rest of the dough with Nutella and pour in as well.
Bake at 160 ° C hot air (convection) or 180 ° C top / bottom heat for approx. 50 - 60 minutes. Do a chopstick test!