First make the strudel dough. For this, knead wheat flour, salt, 1 tablespoon of olive oil, 3 drops of apple cider vinegar, and 180 ml of lukewarm water into a smooth dough.
On a wooden board, drizzle another tablespoon of olive oil, spread a little, and continue kneading the dough ball on it until it is slightly oily all over. It is best to rest in the refrigerator overnight, but at least an hour.
For the filling, prepare the vegetables. To do this, scrape and chop the carrots, break up the broccoli into small pieces, blanch both in boiling salted water for 5 minutes and rinse with cold water.
Clean and chop the pak choi, onions, mushrooms and peas. Put the vegetables in a large bowl .
For the bechamel, melt 3 tablespoons of butter in a saucepan, dust with 5 tablespoons of flour and pour 250 ml of milk. Stir with a whisk until the mixture thickens. Season with salt and nutmeg, grate the cheese and mix into the warm mixture.
Pour the cheese bechamel into the bowl with the vegetables and mix everything well.
Spread a strudel cloth on the kitchen table, dust it with flour, put half of the dough on it and slowly pull it over the edge of the table into a thin dough – you must be able to read the newspaper through the dough!
Divide the filling between the two halves of the dough, roll it up using the strudel cloth and place it on a baking sheet. Brush with a little olive oil and bake at 180 °C for about 30 minutes. Serve with salad and herb dip.