Rinse the rice and cook according to packet instructions.
Place the beef in a shallow dish with the oyster sauce, sesame oil and a grind of pepper.
Once the rice is just about ready, heat a large frying pan or wok over a medium-high heat and stir-fry the beef until well coloured and just cooked.
Add the red onion and capsicum to the pan, and cook for a few minutes until just tender.
Add the char siu sauce and toss to coat.
Serve the beef and capsicum with rice alongside, sprinkle with crispy shallots and coriander.