Cut the onion, cabbage, scallions, and garlic.
On a plate, add the deveined shrimp. Season with salt, white pepper, and cornstarch. Mix well.
In a bowl, whisk together the soy sauce, dark soy sauce, oyster sauce, and chicken stock.
In a pot over high heat, bring water to a boil. Add frozen udon noodles and cook just until they separate. Transfer to cold water to stop the cooking process. Drain well.
In a wok over high heat, add 1 tablespoon of cooking oil. Add the shrimp and garlic, stir-fry for about 1 minute until lightly pink. Remove.
In the same wok over high heat, add 1 tablespoon of cooking oil. Toss in the onion and cabbage. Stir-fry until slightly softened, about 1 minute. Remove.
In the wok over high heat, add 1 tablespoon of cooking oil. Add the udon noodles and stir-fry until heated through. Return the shrimp, vegetables, and sauce. Toss together for about 1 minute until evenly coated and glossy. Finally, add scallions and bean sprouts. Give everything one last toss.
