For the dough, roughly knead flour, 400 g sugar and 300 g butter in pieces with your hands. Add 1 egg, knead everything into crumbles. Cover and chill for about 1 hour.
For the cheese mixture, mix 75 g butter, 300 g sugar and vanilla sugar for about 5 minutes. Stir in the quark in portions. Stir in 6 eggs individually, then add starch. Whip cream until stiff and fold in.
Just press 2⁄3 the crumble on a greased grease pan (approx. 32 x 39 cm) as a base. Spread with plum jam. Spread the cheese mixture evenly and sprinkle with the remaining crumbles. Bake in a preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer) for approx. 40 minutes. Let them cool down. Whipped cream and plum jam taste great 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.