Cooking a Farmer John ham can be made simple by following a few steps. First, preheat your oven to 325°F and place the ham in a shallow roasting pan. You'll want to cook it for about 20 minutes per pound. For added flavor, glaze the ham during the last 30 minutes of cooking. Remember, let your ham rest for 15 minutes before carving to ensure it stays juicy and flavorful.