Preparation Method
1. Gather ingredients and utensils.
2. Marinate sliced beef sirloin with soy sauce and cornstarch in a bowl for 15 minutes.
3. Slice one bell pepper and one onion, and mince two cloves of garlic.
4. Heat one tablespoon of vegetable oil in a skillet over medium-high heat.
5. Add marinated beef to the skillet in a single layer and stir-fry for 3 to 4 minutes until browned. Remove and set aside.
6. In the same skillet, stir-fry bell pepper, onion, and garlic for 3 to 4 minutes until tender but crisp.
7. Return beef to the skillet, add beef broth, oyster sauce, and sugar. Stir and cook for 2 to 3 minutes until the sauce thickens.
8. Season with salt and pepper to taste.
9. Serve garnished with chopped green onions and sesame seeds.
