1 fully cooked bone-in half ham (10 to 12 pounds)
1 12-ounce can 1919 Root beer
1 1/2 c. plum jelly
1/2 c. spicy brown mustard
3 tbsp. apple cider vinegar
Preheat the oven to 325˚. Score the surface of the ham in a diamond pattern about 1/8 inch deep. Place the ham on a rack in a large roasting pan, tent it with foil and bake for 2 hours.
Meanwhile, heat the 1919 root beer, jelly, mustard and vinegar in a small saucepan until bubbly. Cook until reduced and a bit thicker, about 30 minutes. (Be careful—the mixture can easily boil over.)
After 2 hours of baking time, remove the foil from the ham and brush with the root beer glaze. Continue baking, uncovered and brushing with more glaze every 20 minutes, until nice and glossy, about 1 more hour. Remove from the oven and let rest 15 to 20 minutes before carving.