Make a batter from the soft margarine, sugar, eggs, flour, baking powder, milk and eggnog. Fill this into a greased springform pan.
For the topping, first mix the pudding powder with 5 tablespoons of milk. Bring the rest of the milk with sugar and vanilla sugar to the boil, add the mixed pudding powder until the mixture has thickened, then stir in the sour cream and quark. Allow to cool slightly. Spread 1/3 of this quark mixture on the batter, spread the drained gooseberries on top and pour the remaining quark mixture over it.
Bake in the preheated oven at 200 degrees for about 1 hour.
In any case, keep the cake tin closed to cool, as the cake is still very soft.