1 (5-7 lb) Ham, fully cooked (bone in)
1 cup Brown sugar, packed
2 tsp Prepared mustard
1-2 tsp Cider vinegar
Score ham about half-inch deep with a sharp knife. Place ham on a rack in a shallow baking pan. Bake at 325 degrees for 2 to 2-1/2 hours (20 minutes per lb). Combine brown sugar, mustard and enough vinegar to make a thick paste. During the last hour of baking, brush glaze on ham every 15 minutes.