Preheat the oven to 325°F. In a small mixing bowl, combine 2 Tbsp dijon mustard, 1/4 cup brown sugar, and 1/4 cup orange juice. Brush the mixture all over the entire ham.
Place the ham in a roasting pan and cover tightly with a lid or aluminum foil. Roast 12-15 minutes per pound.
In a small saucepan, combine the remaining mustard, orange juice, brown sugar, and all of the spices. On medium-high, bring the mixture to a boil. Add the cornstarch and whisk vigorously. Turn the heat down and simmer for another two minutes or so, until thickened. Remove from the heat and cool.
15 minutes before the ham is done cooking, remove it from the oven and turn it up to 425°F.
Brush the glaze that you made on the stovetop all over the top of the ham, then return it to the oven for the remaining 15 minutes, or until the glaze has caramelized and the ham's internal temperature reads 160°F.