- Combine the beef with 1 tbsp oyster sauce in a bowl. Marinate for 15 mins.
- Heat fry pan or wok over medium-high heat. Add oil and stir-fry the garlic for 1 min. Add beef and stir-fry for 4-5 mins.
- Add capsicum and stir-fry for 2-3 mins. Add chilli garlic sauce, remaining 2 tbsp oyster sauce and stir-fry until heated through.
- Serve sprinkled with the sliced spring onion.