Lamb rib chops are small and don’t take long to cook. They can be cooked rare at an internal temperature of 120F on an instant-read thermometer. For medium rare to medium, cook to 125F-130F. Feel free to continue cooking until you reach your desired doneness, but do note that the chops call for a "rest time" where the inside will continue to cook as it sits. It can be very easy to overcook lamb chops resulting in tough, chewy meat.