Knead the ingredients for the shortcrust pastry together and refrigerate for at least half an hour.
Line a 26 cm springform pan with the rolled out dough.
For the topping, stir the quark with egg yolk, sugar, possibly vanilla sugar, starch or custard powder until creamy. Fold in the egg whites, which have been beaten to stiff snow. Spread on the shortcrust pastry and spread the washed and drained rock pears on top.
Prepare the crumble from butter, sugar, flour and possibly cinnamon and spread on the rock pears.
Bake in the oven preheated to 200 ° C top / bottom heat for approx. 50 - 60 minutes on the middle rack.
Rock pears are a local wild fruit and taste like blueberries with marzipan. They should be picked when fully ripe, dark purple.