Make the Marinade first by combining all the ingredients in a large bowl and mixing well. Place the beef cubes in the Marinade and mix until well coated. Allow to marinate for at least 30 minutes.
Heat the oil in a wok or large saucepan over high heat and stir-fry the onion and garlic until fragrant, 30 seconds to 1 minute. Add the marinated beef and the Marina