Remove ham from refrigerator and allot to come to room temperature (30 minutes or so). Preheat oven to 450°F Score ham cutting through the skin only, leaving fat intact. Season ham with salt and pepper. Place ham, cut side down, in roasting pan. Roast 20 minutes.
Meanwhile, puree mango chutney, broth and hot sauce in a blender or food processor to make glaze.
Reduce temperature on oven to 325°F Remove ham from oven and scatter garlic and onions into the pan. Baste ham with some of the glaze. Cover ham with parchment paper and then foil. Bake 3 1/2 hours to 4 1/2 hours, basting occasionally with glaze and pan juices.
Place potatoes around ham in pan about 45 minutes before it is done; toss to coat. Ham is done when it reaches an internal temperature of 160°F Let rest 20 to 30 minutes before carving. Strain juices and pass with ham.