Roll out the puff pastry and preheat the oven to 200 ° C.
Peel and slice the apples and drizzle with a little lemon juice.
Spread the quark on the puff pastry and sprinkle with sugar and cinnamon. Spread the grated apples on top and also pour the sliced apricots on top. Sprinkle again with sugar and if you like, you can add raisins. Scatter the walnuts on top and, if the fruits are very juicy, sprinkle some breadcrumbs on top.
Carefully roll up the strudel and place on a baking sheet.
Pierce with the fork several times and, if necessary, brush with a beaten egg. Bake in the oven for 20-30 minutes until golden.
Sprinkle with powdered sugar while it is still lukewarm and serve.