Wash the lemon thoroughly and rub dry. Finely grate the peel and squeeze the juice. Drain the apricots well. Put 2 halves aside. Beat the eggs, sugar, vanilla sugar and salt until creamy with the whisk of a hand mixer.
Add quark, lemon zest, 3 tablespoons of lemon juice and pudding powder and stir in. Pour half of the quark mixture into a well greased springform pan (24 cm Ø) sprinkled with semolina. Mix apricots with flour and spread evenly on the quark, add the remaining quark mixture and smooth it down.
Bake in the preheated oven (electric cooker: 175 °C/ gas: level 2/ convection oven: not suitable) for approx. 1 hour. Take the cake out of the oven, loosen the edge of the springform pan with a knife and let it cool down on a grid.
Dust with icing sugar and serve with remaining apricots and decorated with mint.