Rinse the raisins and boil for 5 minutes over low heat or pour boiling water for 10 minutes. Drain the water and cool the raisins. Wash the apples and pears, remove peels and seeds, and cut into small cubes. Place the cookies in a bag and crush them using a rolling pin. Heat the butter in a water bath or in the microwave, then mix with the cookies. Wash the lemon and squeeze the juice out of it. Thaw the dough under a clean kitchen towel. Preheat the oven to 180 degrees.
Prepare the filling. Heat the frying pan. Place the nuts on it and lightly fry them without adding oil. Remove dry films and then grind the nuts in a blender. Place the apples and pear in a bowl, pour in lemon juice to prevent the apples from darkening. Add cinnamon and stir.
Prepare the phyllo dough. Place a sheet of dough on a kitchen towel and brush it with a thin layer of sour cream. Place the next sheet on top and also spread with sour cream. Repeat these steps with all the sheets, try to do everything quickly and accurately. The dough is thin, dries quickly and breaks easily if not handled carefully.
Add the filling to the dough. Place cookies mixed with butter on the top sheet of dough, greased with sour cream. Then sprinkle in the toasted walnuts. Arrange apples and pears, add raisins and sprinkle sugar on top. Brush the edges of the dough with egg wash and use a kitchen towel to roll the dough into a log.
Bake the strudel in the oven. Place parchment paper on a baking sheet and grease it with butter. Using a towel, transfer the strudel to a baking sheet. Brush the strudel with egg on top and place the baking sheet in a preheated oven for 30 minutes at 180 degrees.
After cooking, cool the strudel slightly, then sprinkle with powdered sugar. Serve dessert with a scoop of ice cream.