Follow these simple steps to make your Pepper Steak with Bell Peppers and Onion:

1. Prepare the Beef: Slice the flank steak or sirloin into thin strips against the grain.
2. Marinate: In a small bowl, combine soy sauce, cornstarch, and black pepper. Add the beef and toss to coat evenly. Let it marinate for about 10 minutes.
3. Heat Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.
4. Cook Beef: Add the marinated beef to the skillet in a single layer. Allow it to sear without stirring for about 2 minutes to develop a nice crust. Flip the beef and cook for another minute until it’s browned but not fully cooked. Remove the beef and set aside.
5. Sauté Vegetables: In the same skillet, add the sliced onions and bell peppers. Stir-fry for about 3-4 minutes until they are slightly softened.
6. Add Aromatics: Add minced garlic and ginger (if using) to the vegetables, cooking for an additional minute until fragrant.
7. Combine Ingredients: Return the beef to the skillet, along with the beef broth. Stir well to combine and bring everything to a simmer.
8. Thicken Sauce: Allow the mixture to cook for an additional 2-3 minutes until the beef is cooked through and the sauce has thickened. If desired, drizzle sesame oil over the top for added flavor.
9. Serve: Remove from heat and serve immediately over cooked rice.

By following these straightforward steps, you’ll create a delicious Pepper Steak with Bell Peppers and Onion that’s sure to impress.