Prep the Chinese broccoli by cutting the stems (or stalks) off the leaves first. Slice them, then roughly chop the leafy part, set aside. In a small mixing bowl, combine cornstarch and water, stir until the cornstarch dissolved (this is the slurry), set aside.
Heat the wok with 2 tablespoons of oil. Add the minced pork (or ground pork), season with salt and pepper, cook until browned. Transfer to a bowl and set aside. Drain the liquid and wipe the wok with a paper towel.
Add the rest of the oil into the wok. Saute onion, garlic, and ginger, season with salt and pepper, stir, cook for a minute or until fragrant. Add the broccoli stems, stir, cook until tender. Add the mushrooms and the broccoli leaves. Stir, cook until the leaves are wilted.
Add soy sauce, Shaoxing wine, brown sugar, oyster sauce, stir to combine. Add the meat and red chilis. Stir the slurry to make sure the cornstarch is completely dissolved, add into the pan, stir until well heated and sauce is thickened. Serve immediately with steamed rice.