Preheat oven to 325 degrees. Cut away any skin and trim the fat to a thickness of 1/4 to 1/2-inch. Place the ham, fat side up, in a shallow roasting pan lined with foil (since the sugar in the glaze can burn). As a rough guide, roast a fully cooked ham for about 10 minute per pound. A whole ham should cook in 2 1/2 to 3 hours, a half ham in 1 1/2 to 2 hours. Check the temperature after the minimum time with an instant-read meat thermometer. It should read 130 to 140 degrees. If not yet at the desired temperature, check it every 15 to 20 minutes. Serve the ham as is after a 20 to 30 minute rest or proceed to glaze it.
To glaze: when the ham is warmed through, raise oven temperature to 425 degrees. Remove the ham from the oven and score the surface of the fat to make a crisscross grid. Spread glaze generously over the surface of the ham. Bake about 20 minutes, basting with pan juices a few times. Remove the ham from the oven, cover loosely with foil, and let rest for 20 to 30 minutes before carving Serve with Vanilla Maple Sauce