Wash and prep your cabbage, kale, and broccoli. We usually soak our vegetables in a large stainless steel mixing bowl of cold water, changing out the water 1-3x and letting the vegetables drain in a colander while we prepare the other ingredients.
Heat your wok or large/deep skillet over high heat. When it starts to lightly smoke, add the oil, followed by the broccoli. Cook for 1-2 minutes.
Add the garlic, followed by both the cabbage and kale. Stir to combine, and sprinkle with salt. Stir-fry, using your wok spatula to mix the vegetables so they get contact with the hot sides of the wok.
As the liquid starts to dry out, pile the vegetables in the center of the wok, add a ¼-½ cup of water. If your pan has trouble maintaining high heat, stick to the low end of the range. Cover and let steam for 2 minutes.
Add the vegetarian oyster sauce, if using. Stir to combine and salt to taste once again if needed. If you like your vegetables more well-done, cook for another minute or so.
Transfer to a plate and serve with your favorite Chinese dishes!