For the eight sponge bases, cream the butter until smooth, then add the sugar and vanilla sugar and stir until the sugar has dissolved. Beat in the eggs one by one. Now mix the cornflour, baking powder, flour and salt and add to the mixture by the spoonful, finally folding in the rum.
Cut out two circles from parchment paper to fit two springform bases (26 cm ø). Brush the paper a little with butter on the underside so that it sticks a little to the springform bases.
Preheat the oven to 200°C top and bottom heat and spread two and a half tablespoons of batter thinly on the first paper-lined springform base for the first cake layer. Put this first base in the oven for seven to eight minutes while it bakes, spread the second springform base in the same way as the first and put it in the oven when the first one has finished baking.
Carefully remove the baked bottoms from the baking sheet to cool, but keep the paper on it for the next cake layer. Evtl.
In between, brush the surface of the paper with a little butter. Proceed in this way with all eight bases. If there is enough dough left for a ninth cake layer, bake it in the same way as the previous ones.
When all the bases have cooled (this only takes a few min because they are so thin), cook the filling: To do this, break the marzipan into small pieces and blend them with the apricot jam and the cherry brandy using a hand blender.