Trim skin off ham, leaving thin layer of fat. Score fat in diamond pattern. Set ham, fat side up on rack in shallow roasting pan; add 2 cups (500 mL) water to pan. Cover top of ham with parchment paper, then whole pan with foil. Roast in 325°F (160°C) oven for 2 hours (or according to instructions on ham package) or until meat thermometer reaches an internal temperature of 140°F (60°C).

Meanwhile, in small saucepan, whisk together honey, mustard, rosemary, garlic and cayenne.

Remove ham from pan; set aside. Reserve 1/2 cup (125 mL) of the drippings, discard remaining drippings in pan. Return ham, uncovered, to pan. Add half of the reserved drippings and butter to honey mixture, stirring to melt butter. Brush liberally over ham; roast for 20 minutes, basting after 10 minutes. Remove to platter and tent with foil. Let stand for 15 minutes before carving. Add remaining drippings to glaze and heat over medium heat until bubbly; pour into gravy boat.