For the base, melt 100 g butter and let it cool down a little. Finely crumble the biscuits in the universal chopper and knead them with the liquid butter. Press the crumb mass to the base in a greased springform pan (26 cm Ø). Pre-bake in a preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 10 minutes. Let cool down a little.
For the apple mixture, wash, quarter, core and dice the apples. Melt 50 g butter in a pan. Steam apples, cinnamon and 1 tbsp. sugar for about 5 minutes. Drain in a sieve and collect the stock. Let it cool down.
For the quark mixture, mix 100 g soft butter and 150 g sugar until creamy with the whisks of the mixer. Stir in the eggs one by one. Gradually add starch, quark, rum and apple stock.
Approx. 1⁄3 Spread the quark mixture on the floor and spread approx. 2⁄3 apples on top. Spread the rest of the quark mixture and apples on top of it one after the other. Sprinkle with flaked almonds and 1 tbsp. sugar. Bake in a hot oven at the same temperature for about 1 hour. Let it rest in the switched off oven for about 30 minutes. Remove from the oven and leave to cool for at least 3 hours. Dust with icing sugar. Whipped cream tastes good with it.
That way there's no cracks: After half the baking time, take the cake out of the oven, make a 1 cm deep cut all around between the cheese mixture and the edge of the mould or short pastry and then finish baking.
Stay in shape: After baking, leave the cake to cool for about 1 hour in the open oven when switched off. Then the cake will not collapse so much.
Ready to serve: To cut the cheese, the cheese mixture must be very firm. Place the cake in the mould, preferably on a grid, and let it cool completely. This can take up to 7 hours depending on the height.