Cut beef and peppers into strips about 1 cm wide. Peel and finely dice onions. Heat oil in frying pan, fry meat heartily in portions, remove from frying pan.
Sauté onions and peppers in the frying fat until translucent, gradually add soy sauce and white wine, as well as a quarter of a liter of water. Mix the juice of one lemon with the cornstarch and bring to the boil with the vegetables. Add the meat and season with pepper, salt and a pinch of sugar.
Note: Roast or pull meat longer perhaps, so that it becomes cooked.
* By chef Jürgen Maiberg, Restaurant Arcade, Bochum