Steps
1. In a bowl, marinate the beef strips with soy sauce, oyster sauce, and cornstarch for 15 minutes.
2. Heat vegetable oil in a pan over medium-high heat.
3. Add minced garlic and stir-fry until fragrant.
4. Add marinated beef strips and cook until browned.
5. Toss in sliced onion and bell pepper, stir-fry until vegetables are tender.
6. Season with salt and pepper to taste.
7. Serve hot and enjoy!