Let the ham sit at room temperature, 30 minutes to 1 hour.

Prepare the grill for indirect cooking. Place a shallow roasting pan under the portion of the grill that will not have direct heat. Pour 2 cups water into the pan, add a few orange slices and a couple of springs of rosemary. Preheat the grill to 325°F.

Score the fat with a sharp knife in a 1-inch crosshatch pattern without cutting through to the meat. Place the ham, fat-side up, directly on the grill above the roasting pan.

Bake until a thermometer inserted into the ham registers 110°F, 2 to 2 ½ hours, adding another 1 cup water to the pan if the liquid evaporates.

While the ham is baking, prepare the glaze.

In a saucepan, boil cranberries, cranberry juice, orange juice and maple syrup with Dijon mustard over medium heat until syrupy, about 10-15 minutes. Remove from the heat and stir in rosemary.

Brush the glaze all over the ham glaze. Continue cooking, brushing with the glaze twice more, until the glaze is caramelized and the thermometer registers 140°F, 1 ½ to 2 more hours (total cooking time will be 15-18 minutes per pound). 40 minutes before total cooking time, arrange 6-8 orange slices on top of the ham and continue cooking (this is purely for presentation and totally optional!)

Transfer the ham to a cutting board or platter and let rest 15 to 20 minutes.

Carefully remove the grill grate, then strain the remaining pan juices into a saucepan and boil until slightly syrupy. Spoon the reduced pan juices over the ham.

(Optional) garnish with orange slices, pomegranates, and rosemary.