1.Preheat oven to very hot (240°C/220°C fan-forced).
2.To make spice rub: combine all ingredients in a small bowl.
3.Rub half the spice rub over lamb. Heat the oil in a medium flameproof baking dish, cook lamb until browned all over. Transfer dish to oven roast for 10 minutes.
4.Combine the remaining spice rub with vegetables in a medium baking dish. Roast alongside the lamb for 15 minutes. Remove the lamb; stand, covered, for 10 minutes.
5.Roast vegetables for a further 5 minutes or until tender.
6.Serve lamb sliced with vegetables and lemon wedges, if desired