PREPARATION:
- Prepare grill for direct cooking.
- Combine mustard and garlic in small bowl; spread half of mixture over one side of lamb. Sprinkle with half of chopped rosemary; pat into mustard mixture. Turn lamb over; repeat with remaining mustard mixture and rosemary. Insert meat thermometer into center of thickest part of lamb.
- Place lamb on grid. Grill, covered, over medium coals 35 to 40 minutes or until thermometer registers 160°F for medium or until desired doneness is reached, turning every 10 minutes.
- Meanwhile, soak rosemary sprigs in water, if desired. Place rosemary sprigs directly on coals during last 10 minutes of grilling.
- Transfer lamb to carving board; tent with foil. Let stand 10 minutes before carving into thin slices. Serve with mint jelly, if desired.
