Black bean sauce is made from fermented black soybean mash and can be found at most Asian markets. It has a delicious savory flavor and coats the other ingredients very nicely.
In a wok, heat 2 tablespoons of the oil, add the noodles, and stir quickly, then add the soy sauce and stir well. Transfer to a serving dish.
Add the remaining 2 tablespoons oil to the wok, add the garlic, and stir-fry until golden. Add the pork and stir-fry for 1 minute.
One by one, add the black bean sauce, fish sauce, pork stock, cornstarch mixture, broccoli, sugar, and white pepper, stirring well after each addition. Stir-fry until the pork is cooked through, then transfer to the noodles and serve.