Heat the Oils: Place the vegetable oil and sesame oil in a wok or large skillet over medium heat. Let the oil heat until it shimmers, which helps create that classic stir-fry flavor.
Cook the Vegetables: Add the sliced onions and cabbage to the wok. Sauté for about 8 minutes, stirring occasionally, until the onions are soft and the green cabbage is tender but still slightly crisp.
Boil the Noodles: While the veggies are cooking, bring 8 cups of water to a boil in a separate pot. Add the chow mein noodles and cook according to the package directions, usually around 2 minutes. Drain well and set the cooked noodles aside in a small bowl.
Add Garlic and Ginger: Stir the minced garlic and ginger into the wok with the vegetables. Cook for about 1 minute, just until fragrant, being careful not to burn them.
Make the Sauce: Pour in the oyster sauce and soy sauce▢, tossing everything together to coat the vegetables. Let it cook for another minute, until the flavors have combined.
Combine with Noodles: Add the cooked noodles to the wok and stir-fry everything together until the noodles are evenly coated in the sauce and mixed with the cabbage and onions.
Season and Serve: Taste and adjust with salt and black pepper as needed. Remove from heat, serve hot, and enjoy your homemade cabbage chow mein!