Rub lamb with salt and pepper. Mix ingredients of glaze together and coat lamb. Place lamb on rack in pan and roast at 350 degrees for about 1 1/2 hours, basting occasionally. Internal temperature of lamb should be 130 degrees (rare) to 145 degrees (medium) on meat thermometer. Let lamb rest about 15 minutes before carving. Mint Sauce: Strip off mint leaves and finely chop. Dissolve sugar in boiling water in sauce pot. Add mint and stir in vinegar to taste.