Preheat the oven to 250 degrees. Mix the cranberry sauce, honey, brown sugar, and sherry together in a heavy saucepan and stir over low heat until the mixture attains a sauce-like consistency. Remove from heat.
Place the ham in a roasting pan and score the top of the ham with a sharp knife. Spoon about one-third of the glazing sauce over the ham and place in the oven. Apply glazing sauce to the ham every 30 minutes. Cook ham for a total of one hour and 30 minutes.