Knead the flour, egg, oil, salt, sugar and water first with the dough hook of the hand mixer, then knead with your hands for at least 10 minutes. Alternatively: Knead all ingredients in the food processor for five minutes to form a smooth dough. Shape the dough into a ball, brush with oil and let rest for 45 minutes under a bowl that has been rinsed with hot water.
Roll out on a well floured cloth (1 x 1 m) into a rectangle of 30 x 40 cm. Pull with the backs of both hands to a size of 60 x 50 cm. Put the filling on top so that a 3 cm wide border is created all around. Roll up the strudel with the help of the cloth, fold the sides down and place on a baking sheet lined with baking paper. The baking time depends on the filling.
This recipe is completely foolproof. I had never thought of myself having a strudel before, but this one is guaranteed to be a success.