Step 1

Combine beef with half the sherry, half the soy sauce and half the sweet chilli sauce in a medium bowl.

Step 2

Heat half the vegetable oil in a wok over high heat; stir-fry beef, in batches, for 2 minutes or until browned. Remove from wok.

Step 3

Heat remaining vegetable oil in wok; stir-fry onion and garlic, for 3 minutes or until onion softens. Add capsicum and choy sum; stir-fry until vegetables are tender.

Step 4

Return beef to wok with remaining ingredients; stir-fry until hot.