Heat the oil in a non-stick frying pan or wok. Trim any fat from the steak, cut into thin strips and add to the pan. Stir-fry for 1–2 minutes to seal, add the garlic, peppers, broccoli florets and spring onions, along with 2 Tbsp water. Stir fry for 3 minutes, add the pak-choi and sweet chilli. Allow to heat through thoroughly and serve immediately.