Put the flour and sugar in a bowl and make a depression in the middle. Warm the milk lukewarm. Crumble the yeast in a small bowl. Add 100 ml milk and stir until smooth. Pour yeast milk into the flour bowl and mix with some flour from the rim. Cover with flour and leave to rise for about 15 minutes
Meanwhile melt butter and let it cool down lukewarm. Add butter, egg, remaining milk and vanilla sugar to the flour and knead to a smooth dough. Cover the dough and let it rise for about 30 minutes
Grate marzipan into a bowl. Add the sour cream and liqueur and mix to a thick, smooth cream
Knead the dough on a floured work surface and roll out rectangularly (approx. 32 x 39 cm). Put the dough on the greased fat pan of the oven and let it rise for about 20 minutes, covered
Spread marzipan cream on the yeast dough. Wash and core the apples and slice or cut them into thin slices. Spread apple slices densely on the cake and brush with some lemon juice. Bake the cake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 18-20 minutes. Remove from the oven and let cool off lukewarm
waiting time approx. 1 1/2 hours