Slice steak into thin slices, no more than 1/8 inch thick. Partially freezing the steak beforehand makes this much easier. Add to bowl with baking soda, corn starch, light soy sauce, dark soy sauce and 2 teaspoons neutral oil. Marinate for 30 minutes, or up to an hour.
Place the noodles in a large bowl and completely cover them in boiling water from a kettle. Soak them for 3 to 5 minutes, until rehydrated and partially softened. (I prefer the whole 5 minutes.) After soaking, rinse the noodles under cold running water and drain well. Add about ¼ teaspoon oil and work it through the noodles, separating them with your fingers.
Mix sauce ingredients: 2 tablespoons light soy sauce, oyster sauce, dark soy sauce, fermented soybeans, water, sesame oil and sugar.
Heat wok over a high flame until smoking hot. Add 3 tablespoons oil, swirl around wok, then add beef slices. Sear briefly, then stir-fry quickly until steak is lightly browned and just barely pink in spots. Remove to a plate.
If your beef stuck (which it shouldn't have if your wok was hot enough before adding it and you used sufficient oil), wash wok and return to high heat. When hot, add 3 generous tablespoons more oil and the ginger. Cook briefly. Add the noodles to the wok, spreading them out, and sear over high heat briefly, then flip them over and sear the other side. Do not overcook at this stage, as the goal is to soften the noodles but keep them intact.
Add scallions to the wok and continue gently flipping and mixing noodles. Add Shaoxing wine in around the perimeter of the wok. Add back beef, then mix in the sauce. If the wok is too dry and noodles are starting to stick, add water a couple tablespoons at a time. Add bean sprouts and white pepper, mix briefly, then remove and serve piping hot.
