Preheat oven to 325°. In a small bowl, combine the brown sugar, marmalade and mustard; set aside. Score the surface of the ham, making diamond shapes 1/2 in. deep; insert a whole clove in the center of each diamond. , Place ham cut side down on a rack in a shallow roasting pan. Bake, uncovered, until a thermometer reads 140°, about 2 hours., Brush ham with some of the glaze. Bake 45 minutes longer, brushing with glaze every 15 minutes. Serve remaining glaze with sliced ham.