Creating Pepper Steak with Bell Peppers and Onion is straightforward. Follow these step-by-step instructions:

1. Prepare the Beef: In a bowl, combine the sliced flank steak, soy sauce, and cornstarch. Mix well and set aside for about 10 minutes to marinate.
2. Heat the Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat until shimmering.
3. Cook the Beef: Add the marinated flank steak to the skillet in a single layer. Cook for about 2-3 minutes, flipping halfway through until browned. Remove the beef from the pan and set aside.
4. Sauté the Vegetables: In the same skillet, add the sliced onion and bell peppers. Stir-fry for 3-5 minutes until the vegetables are tender-crisp.
5. Add Aromatics: Stir in the minced garlic and fresh ginger. Sauté for about 30 seconds until fragrant.
6. Combine: Return the cooked flank steak to the skillet with the vegetables. Stir in the oyster sauce if using and toss to combine evenly. Cook for an additional 2 minutes.
7. Season: Taste and adjust seasoning with salt and pepper as needed.
8. Serve: Serve the pepper steak hot over cooked rice or on its own for a low-carb option.

By following these simple instructions, you’ll create a mouthwatering Pepper Steak that everyone will love!