Mix flour, 1 teaspoon sugar and 1 pinch of salt in a bowl. Add 100 g butter in pieces and about 100 ml cold water. Knead first with the dough hooks of the hand mixer, then briefly with your hands to a smooth short pastry. Wrap the dough in foil and chill for approx. 30 minutes
Mix the poppy seeds, 50 g sugar and 1 packet of vanillin sugar. Mix the quark, 50 g sugar, 1 egg, 1 packet of vanillin sugar and 1 pinch of salt with the whisks of the hand mixer. Mix nuts, 50 g sugar and 1 packet of vanilla sugar. Peel apples, quarter them and cut out the core. Cut quarter into slices, mix with 75 g sugar and cinnamon. For the glaze, mix sour cream and 3 eggs with a whisk
Let the dough sheets rest at room temperature for about 10 minutes. Grease the springform pan (26 cm Ø) well. Pour the short pastry into the mould and press it to a smooth base, pressing the rim up about 1 cm
Melt 60 g butter. Unroll the filo pastry and place 1 sheet on the shortcrust pastry, brush with butter and fold the protruding edges inwards. Sprinkle half of the poppy seed mixture on top and pour 4 tbsp. Place the next filo leaf on top, brush with butter, fold and spread half of the quark mixture on top. Cover with filo pastry again, spread with butter, add half of the nut mixture and 4 tbsp. glaze. Spread the filo pastry with butter, fold it, cover with half of the apple mixture and pour 4 tbsp. of icing on top. Repeat everything again and finish with 2 sheets of filo pastry
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) on the lower rack for approx. 1 1/4 hours. Remove the gibanica and brush with the remaining butter