Trim the lamb of any fat.
Combine the garlic, mustard, mint, coriander and oil in a small bowl.
Rub the lamb with the garlic and mustard mixture. Transfer to a baking dish.
Bake in a preheated oven, 200°C (400°F), Gas 6, for 10–15 minutes, or until the lamb is cooked to your liking. Leave to rest for 10 minutes, then serve with a selection of steamed vegetables.