Preheat the oven to gas mark 4-5, 180°C, 350°F. Take 2 lean racks of lamb and calculate the cooking time:
Medium - 25 minutes per 450g/½kg (1lb) plus 25 minutes
Well Done - 30 minutes per 450g/½kg (1lb) plus 30 minutes
Mix together rosemary, lemon rind and juice, garlic, olive oil and seasoning, and rub into the racks.
Cook on a preheated barbecue with a lid or place onto a rack in a roasting tray and oven roast for the calculated cooking time.
Serve the lamb with new potatoes and a rocket and grape salad.