For the dough, stir the butter with the sugar until frothy. Mix the flour, nuts and baking powder and stir in with the yogurt.
Press the dough evenly onto the baking sheet, slightly moistening your hands if necessary.
Then put the tray in the refrigerator.
For the crumble mix the flour with the nuts, sugar and cinnamon, add the flaky butter and process everything into crumble of the desired size.
Then place in the refrigerator as well.
Now peel the apples for the topping, quarter them, remove the core and cut into slices about the width of a finger. Put aside.
For the quark cream, mix the pudding powder with 50 g sugar and approx. 4 tablespoons milk, bring the rest of the milk to the boil. Stir in the mixed powder and bring to the boil again, stirring constantly, so that the mass thickens. Take it off the stove.
Beat the eggs with the remaining sugar until creamy, stir in the quark and pudding and also set aside.
Now preheat the oven to 180 ° C top / bottom heat.
Now distribute the apple wedges generously on the prepared nut base. Spread the quark cream on it as evenly as possible and spread the crumble over it.
Bake in the preheated oven for about 60-70 minutes.