Creating Pepper Steak with Bell Peppers and Onion is straightforward if you follow these steps carefully:

1. Marinate the Beef: In a bowl, mix the soy sauce, oyster sauce, and cornstarch. Add the sliced beef and toss to coat. Let it marinate for at least 10 minutes.
2. Prepare the Vegetables: While the beef is marinating, slice the onion and bell peppers. Mince the garlic and ginger.
3. Heat the Pan: In a large skillet or wok, heat the vegetable oil over medium-high heat until shimmering.
4. Cook the Beef: Add the marinated beef to the hot skillet. Quickly stir-fry for about 3-4 minutes until browned but not fully cooked. Remove the beef from the pan and set aside.
5. Stir-Fry Vegetables: In the same skillet, add the sliced onions, red bell peppers, and green bell peppers. Stir-fry for about 3-4 minutes until they are tender-crisp.
6. Add Aromatics: Add the minced garlic and ginger to the vegetables, stirring for an additional minute for flavor.
7. Combine Beef and Broth: Return the beef to the skillet. Pour in the beef broth, add sugar, and black pepper. Stir everything together.
8. Cook Through: Let the mixture cook for another 3-5 minutes until the beef is cooked to your preferred doneness and the sauce thickens slightly.
9. Taste and Adjust: Taste the dish and adjust the seasoning if necessary, adding more soy sauce or salt if desired.
10. Serve: Remove from heat and serve hot over cooked rice.

These instructions simplify the cooking process, allowing you to focus on enjoying your meal!