- In a bowl, combine the thinly sliced beef with soy sauce, cornstarch, sugar, and black pepper. Mix well and let it marinate for at least 15 minutes.
- Heat 1 tablespoon of vegetable oil in a large skillet or wok over high heat. Add the marinated beef slices and stir-fry for 2-3 minutes until browned. Remove the beef from the skillet and set aside.
- In the same skillet, add another tablespoon of vegetable oil. Add the sliced onion and bell pepper, and stir-fry for 2-3 minutes until slightly softened.
- Add the minced garlic and ginger to the skillet, and stir-fry for another 1 minute until fragrant.
- Return the cooked beef to the skillet. Add beef broth (or water), oyster sauce, soy sauce, rice vinegar, and sesame oil. Stir to combine.
- Bring the mixture to a simmer and let it cook for 2-3 minutes until the sauce thickens slightly.
- Stir in the cornstarch slurry to further thicken the sauce. Cook for another minute until the sauce coats the beef and vegetables evenly.
- Remove from heat and serve the Beef Pepper Steak hot over cooked rice.
- Garnish with chopped green onions before serving, if desired.
Enjoy your flavorful Beef Pepper Steak! Adjust the seasoning and spice level according to your preference.