Place all of the marinade ingredients in a bowl and mix well. Add the steak and mix to cover with the marinade. Leave to marinade for an hour.
Heat the oil in a hot wok. Add the beef and the marinade and fry for 3-4 minutes until the meat is browned. Drain off any excess liquid from the beef that may arise from the cooking process.
Add any vegetables you might wish to create a stir fry.