1.Place noodles in a large heatproof bowl, cover with boiling water; stand until just tender, drain.
2.Heat oil in a wok over high heat; stir-fry beef, brown onion and chillies until beef is cooked through. Add wombok and peas; stir-fry until wombok is tender. Add noodles, sauces, stock, vinegar and green onions; stir-fry until hot.
You can use beef strips instead of the mince, if you prefer.