Instructions:

1. Marinate the beef:
Combine 5 tbsp light soy sauce, 3 tbsp oyster sauce, 2 tsp black pepper, and 3 tbsp sesame oil. Add the beef slices and marinate for at least 30 minutes.

2. Cook the beef:
Heat a pan or wok over high heat. Add the marinated beef and cook until browned and cooked through.

3. Add the vegetables:
Add the coriander, and chili peppers to the pan. Stir-fry for a few minutes until the vegetables are slightly wilted.

4. Serve:
Transfer the beef and vegetables to a serving plate and enjoy!