Generously coat the beef with the marinade and set aside for 30 minutes.
Heat a little sesame oil in a large wok over a high heat until smoking. Spread the meat out in the wok and brown. Remove from the wok.
Reduce the heat a little and add the remaining oil. Fry the red onion, pepper, cabbage and mushrooms until golden. Add the garlic and ginger and cook for a few seconds.
Add the remaining ingredients except the stock and cornflour. Add the beef and toss until glazed with the sauce.
Mix the stock and cornflour. Add to the wok and stir-fry for 1 minute.