For the dough, mix flour, sugar and baking powder. Add the egg yolks. Melt the fat, add it and knead everything into crumbles. Spread it on a greased baking tray and press it down with your hand. Put it in a cold place, then spread apple sauce on top. Separate the eggs for the filling.
Cream fat, sugar and vanilla sugar. Add lemon juice, quark, egg yolk and semolina and mix. Beat the egg whites until stiff, fold into the quark mixture and spread on the baking tray. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 45-50 minutes. Dust with icing sugar shortly before serving. Results in approx. 25 pieces