Place the ham on a rack in a foil-lined roasting pan, fat-side up. Roast for 1 hour 30 minutes.
Meanwhile, in a medium saucepan set over medium heat, mix the honey, sugar, cornstarch, cayenne and red pepper flakes together. Stir until a thick glaze forms. Rub half of the glaze on the ham and bake for another 30 minutes.
Add the remaining glaze and cook until a thermometer inserted in the ham reads 140 degrees F, 30 minutes.
Remove from the oven and rest the ham for at least 15 minutes before serving.