Combine the marinade ingredients in a medium sized bowl, and soak the flank steak in the marinade for 1 hour.
In a hot wok over the highest heat, add 3 tablespoons of the oil and black bean sauce. Using the Chinese ladle, spread the bean sauce in the wok until nice roasted smell comes out. Add the beef and stir-fry for 2 minutes. Do not over cook! Remove the beef and set aside.
To the wok, add the remaining 3 tablespoons oil, the peppers, and the crushed garlic. Add the boiled noodles and the marinade for the beef and cook for 2 minutes. Add the bok choy and cook until wilted. Add the reserved beef and toss until heated through. Serve.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.