Wash and drain bean sprouts. Cut onion into thin slices. Cut pork into thin strips, julienne style. Heat wok, adding 1 tablespoon oil. Stir-fry bean sprouts, onion, BBQ pork, and bamboo shoots for 2 minutes with 1/2 teaspoon salt and 1/2 teaspoon sugar. (Do not overcook.) Let cool before using.
In a separate bowl beat the eggs, add oyster sauce and soy sauce; mix well. Add the stir-fried ingredients and mix thoroughly. Heat wok, add 1 tablespoon oil and drop 1/2 C. of the mixture in the wok. Fry about 2 minutes on each side. Place on serving dish and set aside.Repeat procedure with remaining oil and mixture. Pour gravy, over patties and garnish with the chopped green onion and toasted sesame seeds. Toast sesame seeds in a dry frying pan, without oil for 3 minutes.
Bring broth to a boil. Add mushrooms, salt, sugar, pepper and dark soy sauce. Prepare thickening made with the cornstarch and cold water; add the seasoned broth and cook for 1 minute.