1.Combine lamb with half the sherry, half the soy sauce and half the sweet chilli sauce in medium bowl.
2.Heat half the peanut oil in wok; stir-fry lamb, in batches, until browned.
3.Heat remaining peanut oil in wok; stir-fry onion and garlic until onion softens. Add capsicum and broccolini; stir-fry until vegetables are tender.
4.Return lamb to wok with remaining ingredients; stir-fry until hot.
Broccolini is a cross between broccoli and chinese kale; it resembles broccoli in appearance, but is milder and sweeter in taste. It has long asparagus-like stems and a long loose floret, both completely edible. Baby buk choy or gai lan work well in this stir-fry, too; use in place of the broccolini.