First, cut the beef into thin slices. ( To achieve the tender slices, cut the beef against the grain. )
In a mixing bowl add the beef slices and marinade ingredients, mix well and marinate for at least 15 minutes.
Finely chop the ginger and cut all the vegetables into thin slices. Deseed and cut the dry red chillies into half.
In a large wok or pan, add 2 tablespoon of vegetable oil, flatten and sear the marinated beef for 2-3 minutes. Flip and stir fry for another 2 minutes then remove from wok and set aside.
In a clean wok or pan, heat 1 tablespoon oil into medium heat, add the dry chillies and stir for few seconds, follow with the garlic and cumin seeds. Stir for few seconds then add the onion and pepper slices.
After few seconds, place the beef slices back in the wok. Sprinkle cumin powder, black pepper and salt to taste.
Stir well to combine all ingredients evenly. Remove from wok and transfer to serving plate.
Serve immediately with hot steamed rice! Enjoy!