Cut steak across grain in 5mm slices, flatten with mallet. Combine cornflour, soy sauce, egg yolk, bicarb, peanut oil and water in a bowl mix till smooth, add steak and marinate for 1 hour, basting now and then.
Heat oil in wok with ginger, when hot add steak a few at a time and stir fry 2 mins on each side till all meat is cooked. Add sauce and stir fry for another min. Spoon steak and sauce onto plate.
Combine all the sauce ingredients; mix well and set aside.