For the marinade, mix 2 tablespoons of soy sauce and 1 tablespoon of oil with the flour, garlic, pepper and the grated ginger. Cut the meat into thin strips and leave to stand in the marinade for about 1 hour.
Clean and wash the leek and cut into rings. Clean the mushrooms and cut into thin slices. Heat the remaining oil in a pan. Add the strips of meat and stir-fry for about 5 minutes. Add the leek and mushrooms and fry for another 5 minutes.
Deglaze with the meat stock and the remaining soy sauce and simmer the sliced meat over a low heat for about 15 minutes. If pork tenderloin is used, 10 minutes of cooking time is sufficient. Season to taste with salt, pepper and curry powder.
Rice, noodles or spaetzle and salad go well with this.