Thaw the ham. If the ham is frozen, allow it to thaw in the fridge for 1 to 2 days. Then, remove the ham from the fridge and let it rest on the counter for 2 hours before cooking, to come to room temperature.
Prep the roasting pan. Preheat oven to 300°F (150°C). Adjust oven rack to lowest position. Pour 2 cups of water into bottom of roasting pan.
Mix the honey glaze. In a medium bowl, stir together the sugar, honey, orange juice, mustard, and spices.
Brush on the glaze and bake the ham. Place the ham on the baking tray, brush ¼ of the honey glaze on top, then cover the ham with aluminum foil and bake for 10 to 12 minutes per pound (for a 9 pound ham, that's about 1 ½ hours). During this 1 ½ hours you'll re-glaze every 30 minutes.
Caramelize the glaze. After 1 ½ hours, increase the oven temperature to 425°F (220°C), discard the aluminum foil, and brush the remaining ¼ of the glaze all over the ham. Return the ham to the oven and bake uncovered for 15 to 20 minutes, until shiny, glazed, and slightly caramelized.
Slice the ham. Let the ham rest for a few minutes before serving, then slice it up by removing the spiral slices from the flat, wider end first.