01 - In a small mixing bowl, combine the soy sauce, oyster sauce, hoisin sauce, sesame oil, black pepper, sugar, cornstarch, and water. Whisk until smooth and set aside.
02 - Prepare the chow mein noodles according to package directions. Drain thoroughly, rinse under cold water to halt cooking, and set aside.
03 - Heat 1 tablespoon of vegetable oil in a large wok or skillet over high heat. Add the sliced beef in a single layer and stir-fry for approximately 2 minutes until browned on all sides but still tender. Remove from the wok and transfer to a plate.
04 - Add the remaining tablespoon of vegetable oil to the wok. Sauté the garlic, ginger, and sliced onion for about 1 minute until fragrant and the onion begins to soften.
05 - Add the sliced bell peppers to the wok and stir-fry for 2 to 3 minutes until crisp-tender, maintaining their vibrant color and slight crunch.
06 - Return the seared beef to the wok along with the cooked noodles. Pour the prepared sauce over everything and toss continuously for 2 to 3 minutes until all components are evenly coated and heated through.
07 - Transfer to a serving platter, garnish with sliced spring onions, and serve immediately while hot.