Slice the eye fillet steak thinly against the grain. Add soy sauce, black bean sauce, dark soy sauce, sugar, corn starch, and sesame oil. Massage the sauce into the beef and marinate for 15 minutes.
Heat the wok until hot, then add cold oil. Add the beef and spread it out. Sear for 1 minute, flip, and sear for another minute. Toss briefly, then remove and set aside.
In the same wok, add onion and the white part of the spring onion. Stir-fry over high heat until fragrant.
Add the beef back in, then add water, dark soy sauce, MSG, minced garlic, and the green part of the spring onion.
Stir-fry until the sauce becomes thick and glossy. Finish with a little cooking oil for extra shine.
Serve over rice
