1 lb fresh Chinese egg noodles (or use dry spaghetti)
2 tsp peanut or canola oil
1 lb boneless, skinless chicken breast, cut into bite-size pieces
1 small onion, diced, or 4-5 scallions, chopped
1 clove garlic, peeled, sliced thin
4-oz can sliced mushrooms
1/2 cup Cantonese 3-2-1 sauce (3 parts reduced-sodium soy sauce, 2 parts oyster sauce, 1 part sesame oil), or more as needed
2 cups mung bean sprouts (optional), rinsed under cold water
Bring 6 quarts of water to a boil; cook egg noodles over high heat until they float to the surface, then reduce heat and cook for 2-3 minutes until al dente (or cook spaghetti according to package directions). Drain, but do not rinse, and reserve the cooking water.
In a large wok or frying pan, heat the oil. Add the chicken and stir fry for 1-2 minutes, until lightly brown all over. Add the onion, and stir for 1-2 minutes, until translucent. Add the garlic and mushrooms, and stir for 1 minute. Add the Cantonese 3-2-1, plus 1-2 tablespoons of the reserved cooking water, and stir for 1 minute until the meat is coated. Add the cooked noodles and bean sprouts, and stir thoroughly for 2-3 minutes, until the ingredients are combined and the sauce is absorbed into the noodles. If needed, add more soy sauce and oyster sauce, to taste.