Cut the beef into small strips. Mix well with all the other ingerdients and marinate for 24 hours in the fridge. Add a little seasoned oil to a hot wok and stir fry the beef in marinade in small batches (approx 6 batches) for 2-3 minutes until cooked. Keep warm in the oven until all cooked, sprinkle over the spring onion and sesame seeds and serve.