Wash the bean sprouts to give them more time to drain. Boil noodles in salted boiling water until they are soft, but not sticky. Break the noodles in half if desired so they are easier to manage. Blanch the noodles in cold water and drain.* Cut the chicken into thin strips. Add seasoning ingredients to chicken, adding cornstarch last. Marinate chicken in seasonings for 10 to 15 minutes. While chicken is marinating, prepare vegetables. Cut the bok choy diagonally into 1/2 inch thick slices, slice mushrooms. Heat the frying pan on high, add 2 tablespoons of oil and fry the noodles in small portions until they are golden. Use chopsticks to separate the noodles as they are frying. Remove the noodles. Add more oil and add the meat and Onion to the pan. Stir fry until the meat has no redness. Remove from wok or pan. Cook the rest of the vegetables separately, adding a bit of salt if desired to taste. With the bean sprouts and bok choy add a bit of sugar as well if desired. If desired, add about 1/4 cup of water and cover pan while cooking bok choy, as it doesn't contain much moisture. Give the gravy a quick restir. Add all the ingredients back into the wok, making a well in the middle if the wok for the gravy. Mix well. Add green Onions at this point if desired, or save them for a garnish. Pour on top of the noodles. Garnish with sesame seeds. Serve hot. Serves 4 to 6.