Preheat the oven to 325°F
Remove the ham from packaging
Place the ham cut-side down in a roasting pan
Score the surface of the ham in a diamond pattern if desired
Add a small amount of water to the bottom of the pan
Cover the ham tightly with foil
Bake until heated through, about 15 to 18 minutes per pound
Remove the foil during the last 20 to 30 minutes if glazing
Brush with glaze if using
Continue baking until the glaze is set and the internal temperature reaches 140°F for fully cooked ham or 145°F for raw ham
Remove from the oven
Let the ham rest for 15 to 20 minutes before slicing