Instructions

1. In a bowl, combine the soy sauce, oyster sauce, and cornstarch. Add the thinly sliced beef to the bowl and toss to coat. Let marinate for at least 15 minutes.
2. Heat 1 tablespoon of vegetable oil in a large skillet or wok over high heat. Add the beef slices in a single layer, working in batches if necessary, and sear for 1-2 minutes on each side until browned. Remove beef from the skillet and set aside.
3. In the same skillet, add the remaining tablespoon of oil. Add the bell peppers and onion, sautéing for 3-4 minutes until they are tender but still crisp.
4. Add the garlic and ginger to the skillet, sautéing for another minute until fragrant.
5. Return the beef to the skillet. Add the beef broth or water, stirring to combine all the ingredients. Cook for another 2-3 minutes, allowing the sauce to thicken slightly.
6. Season with salt and pepper to taste. Serve hot with rice or noodles.