Mix the cornstarch, soy sauce and the Shaoxing wine. Then slice the beef steak into very thin slices. They shouldn't be thicker than ¼ inch (½ cm). (If you freeze the steaks for 30 minutes before slicing, they are easier to handle as the beef stays firm when you cut it.) Marinate the steaks while you are preparing other ingredients.
Soak or cook the noodles according to package instruction, drain, rinse and set aside.
Make the sauce by mixing together the oyster sauce, light soy sauce, sugar and sesame oil, set aside.
Preheat 1 tbsp of oil in a wok or a very large pan. Cook the beef strips on high heat until done for 5-7 minutes. Remove from the pan to a separate plate.
To the same pan add another tablespoon of oil, then add the drained noodles and stir fry with a pinch of salt and white pepper for about 30 seconds over high heat. (Don’t forget to season the noodles!)
Bring the beef back to the pan together with green onions and been sprouts, toss to combine, then pour the sauce over it, stir until all ingredients are coated with the sauce and warmed through. Taste and add a pinch of salt if needed.