Cut the beef into thin, bite-sized pieces and pound with a meat mallet if you wish. Put meat into a bowl, add soy sauce, pepper, sesame oil and cornflour and mix well. Stand 30 minuntes or longer.
Heat oil in wok and stir-fry meat until browned. Transfer meat from wok to a plate. Add onion and stir-fry for 2 minutes. Stir in garlic and curry powder, then sherry, satay sauce, sugar, soy sauce and water.
Bring to boil for 2 minutes, return meat and reheat.
Serve with steamed rice, broccoli or Asian noodles.