1. In a wok,heat vegetable oil and drop in the minced garlic. Saute it for couple of minutes.
2. Add the onion and the ginger and saute them together until the onions turn translucent.
3. Empty the beef in the wok and cook it until it turns pink in color.
4. Add the diced broccoli stalk and saute it for a few minutes. Cover and cook for 2 minutes.
5. Next add the broccoli florets and give everything a stir.
6. Sprinkle in crushed black pepper.
7. Pour in the oyster sauce.
8. Add the mushrooms and stir. Cover and cook for a few minutes.
9. Meanwhile, mix 1 teaspoon of corn starch in 1/2 cup of cold or tap water.
10.Add the dissolved corn starch.
11.Turn off the stove. The heat of the stove is enough to thicken the sauce.