Cook the Shanghai noodles according to the package instructions. Drain and set aside.
Marinate the meat for 15 minutes.
In a large pan or wok, heat 1 tablespoon of oil over medium-high heat.
Add the protein (shrimp, chicken, beef, or tofu) and cook until browned or cooked through. Remove from the pan and set aside.
In the same pan, add another tablespoon of vegetable oil if needed.
Sauté minced onions, garlic and grated ginger until fragrant.
Add Napa cabbage, carrots, shiitake mushrooms, and scallions. Stir-fry until the vegetables are slightly tender but still crisp.
In a small bowl, mix together soy sauce, oyster sauce, sesame oil, mirin, and white pepper.
Add the cooked noodles and the prepared sauce to the pan with the vegetables.
Toss everything together until the noodles are well coated with the sauce and the vegetables are evenly distributed.
If you cooked protein separately, add it back to the pan and toss for another minute to heat through.
Dish out your Shanghai noodles hot and enjoy the deliciousness!