For the shortcrust pastry, first knead butter in pieces, flour, 50 g icing sugar and 2 tablespoons of ice-cold water with the dough hooks of the mixer, then quickly knead to a smooth dough with your hands. Roll out round (approx. 30 cm Ø) on some flour. Line a greased tart tin with the dough (26 cm Ø), pressing down the edges. Chill for about 1 hour.
For the cheese mixture, stir the quark, eggs, sugar and vanilla sugar until smooth. Stir in poppy seeds and semolina. Drain the apricots in a sieve.
Spread the cheese mixture on the short pastry. Spread the apricots on top with the convexity upwards. Bake the tart in the preheated oven (electric: 200 °C/circulating: 175 °C/gas: see manufacturer) on the lower rack for 30-35 minutes. Let it cool down. Dust with 1 tablespoon icing sugar.
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.