1.Combine beef, onion, ginger, chilli, chestnuts, chives, egg, breadcrumbs, hoisin sauce and two-thirds of the garlic in large bowl; shape mixture into eight patties.
2.Combine the water, oyster sauce, extra hoisin sauce and remaining garlic in small bowl. Reserve ¼ cup hoisin mixture.
3.Brush patties with remaining hoisin mixture; cook patties on heated oiled barbecue until browned both sides and cooked through.
4.Heat sesame oil on barbecue plate; cook gai lan until wilted. Serve gai lan topped with patties; drizzle with reserved hoisin mixture.
Hoisin is a sweet, thick Chinese barbecue sauce made from salted fermented soya beans, onion and garlic. It is available from Asian food shops and most supermarketsNote