Mix flour with salt and sugar, add egg, vegetable oil and water. Knead the dough and leave for 30 minutes.
Peel and grate the apples, add sugar and cinnamon or vanilla, mix well.
Roll out the dough into a layer 2-3 mm thick.
Spread the filling evenly.
Roll into a roll, lay seam down on a greased baking sheet.
Bake for 40 minutes at 180 * C.
5 minutes before cooking, brush the strudel with butter and send it back to the oven. Sprinkle the finished strudel with powdered sugar.