Position an oven rack in the lower third of the oven and preheat to 325 degrees . Place the ham meaty side up on a cutting board and score the rounded side all over with diagonal cuts about 1 1/2 inches apart and 1/4 inch deep, forming a diamond pattern. In the center of each diamond, insert a single clove.
Place the ham in a roasting pan and bake until an instant-read thermometer inserted into the thickest part registers 110 degrees to 115 degrees , about 3 hours.
Meanwhile, in a small saucepan, combine the chicken broth, shallots, prunes, thyme and 1/4 teaspoon salt. Cover and simmer over medium heat for 2 minutes, then stir in the brown sugar, 1/2 cup at a time, until dissolved. Transfer to a food processor, add the vinegar and mustard and process until smooth. Let cool. (You can make the glaze ahead and refrigerate, tightly covered, for up to 2 days.)
Remove the ham from the oven and brush all over with about 2/3 cup of the glaze. Tent loosely with foil, return to the oven and continue to roast, basting with the pan juices and the remaining glaze once or twice, until the ham registers 135 degrees , about 1 hour. Remove from the oven and let rest for 10 minutes before carving.
Why You Should Score Your Meat, Fish and Veggies