Preheat oven to 300 degrees. Put ham, fatty-side up, in a foil-lined metal baking pan. Cover with foil and bake for 3 hours. Combine remaining ingredients. Remove ham from oven. Carefully trim away all but 1/8-inch of fat. Score with a sharp knife in a diamond pattern, making cuts 1/8-inch deep and one inch apart.

Pour excess fat from pan. Line pan with new foil, and put ham in pan. Spoon glaze over ham and bake for 20 minutes. Raise oven temperature to 325 degrees, and glaze again. Bake an additional 20 minutes. Glaze once more and bake 15 minutes. Cool before carving into thin slivers.