Grease a fat pan (approx. 32 x 39 cm; approx. 3.5 cm deep) and dust with flour. Peel apples, cut into eighths, core them and mix them immediately with lemon juice
Mix quark, 80 g sugar, 1 packet of vanilla sugar, salt, oil and milk with the whisk of the hand mixer. Mix flour and baking powder and knead briefly with the dough hooks of the hand mixer
Dust the dough with some flour and form it into a roll. Roll out on the fat pan and press up 1-2 cm with your hands at the edge. Drain the apples if necessary and spread them evenly on the dough
Mix sour cream, eggs, 30 g sugar and 1 sachet vanilla sugar. Pour over the apples. Chop the walnuts and sprinkle over the apples. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for about 35 minutes. Let them cool down