Steps
1. Slice the pork tenderloin into thin strips.
2. In a small bowl, mix together the soy sauce, oyster sauce, sesame oil, and chili flakes.
3. Heat the vegetable oil in a pan over medium-high heat.
4. Add the minced garlic and sauté for 1 minute until fragrant.
5. Add the pork strips and cook for 3-4 minutes until browned.
6. Add the sliced bell pepper and onion, and cook for an additional 2-3 minutes until vegetables are tender-crisp.
7. Pour the sauce mixture over the pork and vegetables, and stir-fry for another minute.
8. Season with salt and pepper to taste.
9. Serve hot with steamed rice or noodles.