For the hazelnut cake, first separate the eggs. Beat the egg whites with a little lemon juice (first without mixing) until stiff. Mix the egg yolks with the sugar and vanilla until fluffy.
Gradually add the oil – finish mixing. Add hazelnuts, eggnog, rum and wholemeal spelt flour to the yolk mixture. Fold in beaten egg whites and bake in a greased and floured springform pan (diameter 20 cm) at approx. 170 °C.
Let cool and cut in the middle. Fill with vanilla cream. Spread some cream on top and on the edges as well. Decorate the hazelnut cake with grated cooking chocolate.