preheat oven to 350. place ham cut side down in roasting pan. add 1/3 cup of water to the pan

score the ham on all sides in a diamond pattern, cutting only 1/4 to 1/2 in. deep. press 1 clove in the middle of each diamond cover the ham with foil and bake for 2 hours.

meanwhile, make the glaze: in a medium saucepan whisk togeather the mustard, vinegar, sugar, and 1/4tsp each salt and pepper. Gradually add root beer. simmer, stirring occasionally. until slightly thickened. 15 to 20 minutes. remove from heat.

brush a third if the glaze about 1/3 cup over the ham and bake, uncovered for 20 minutes, repeat. brush the remaining glaze over the ham and bake until the ham is heated through and the internal temperature registers 140°F. 15 to 20 minutes more