In a mixing bowl, combine the meat pieces and the rest of the marinating ingredients. Mix well to fully blend the flavor and coat the meat with the marinade. Marinate for about an hour inside the fridge.
In a smaller mixing bowl, combine oyster sauce, soy sauce, rice vinegar, sugar, sesame oil, ground pepper and cornstarch solution. Stir well blend the flavors and attain this exotic-looking sauce.
In a wide non-stick pan, heat about ¼ cup oil and stir-fry the marinated beef until almost cooked through and uniformly seared. Take the meat from the pan and set aside.
Cut the broccoli into flowerets and steam them for about 3 minutes or just until cooked through but still crunchy. Do not overcook.
At the same time that the broccoli is being steamed, cooking the beef with the sauce should be carried out. Timing is necessary for the two processes to end at almost the same time.
Using the same non-stick pan, heat about 2 tablepsoons of oil on medium flame. Fry the ginger until fragrant. Add in green onions and continue frying. Return the stir-fried beef and continue sautéing.
Immediately after, add the sauce and continue cooking until it thickens. Thin it out with some broth if necessary. As mentioned above, this point should almost jive with the time the broccoli is done steaming.
In a wide platter, arrange the steamed broccoli. Then carefully pour the meat and its sauce on top of the vegetable.
Serve immediately with steamed rice. You can also eat it on its own or perhaps with bread.