Boil water to cook the thin spaghetti noodles, al dente.
Add oil into preheated wok. Tilt the work to coat the sides of wok with oil.
Add the chopped pork. Gently break 'em apart as you stir. Cover the wok to cook the pork. Create a space in the middle. Add the onions and garlic to saute. Cover it back up to continue cooking for a couple of minutes.
Stir in the julienned carrots. Add the sauce mixture of soy sauce, water, Worcestershire sauce, and sesame oil. Sprinkle black pepper, stir more, then cover to let the liquid boil.
Once the liquid boils, stir in the napa cabbage. Cover to cook and let the napa cabbage soften a bit.
Add the cooked noodles into the wok then stir everything together. Stir in the sliced button mushrooms in the end. Turn the stove off. The heat from the wok and noodles will finish cooking the mushrooms.