how long to cook lamb rack
1 Put the lamb racks into a baking dish and spoon on any sauce that may be left behind on the plate. 2  Bake for 20 minutes for mediumârare, or until cooked to your liking, basting a couple of times during cooking with the honey mustard mixture. Cut small slits in the top of the lamb with a small, sharp knife. 2  Insert slices of garlic and small pieces of rosemary into the slits. 3  Sit the lamb on a plate. 4  Whisk together the honey, wholegrain mustard and mint sauce then brush over the lamb racks. 5  Allow to marinate for 20 minutes in a cool place.