New Zealand hams are famous for the natural, dry curing process used to enhance the flavor and preserve the meat. While traditional quick-cure processing calls for soaking the raw pork leg in a brine solution to plump up the meat and evenly distribute preservatives, dry curing uses a salt or salt-and-sugar rub on the outside of the raw pork leg to remove the water from the meat, allowing natural preservation. Considerable shrinkage occurs during the dry cure process -- the ham loses up to 12 percent of its weight through water loss, which needs to be replaced before cooking. In some regions of the U.S., dry cured ham is also called country ham, Tennessee, Virginia or Kentucky ham.
Remove any cloth, paper or other wrapping material. Scrub the outside of the ham in a large basin of cool water with a stiff brush to remove salt crystals and any mold that may have developed. Mold occurs naturally on the outside of the ham during the aging phase, and it is not dangerous.
Place the whole, scrubbed ham in the basin and refill the basin with enough cool water to cover the ham. Allow it to soak for 12 hours or overnight. Soaking replaces the moisture that was removed during the curing process as it reduces the salt content of the ham. If you notice small salt crystals forming as the ham soaks, you can scrape them off and replace the soaking water, if you wish.
Remove the ham from the basin and place it into a large cooking pot. Fill the pot with fresh water so the ham is submerged. Bring the pot just to a boil, then reduce the heat to a slow simmer. Simmer the ham for 20 to 25 minutes per pound.
Take the ham from the pot, slice through the skin with a sharp knife, and remove the skin. Trim away heavy fat, leaving a thin layer about 1/4 inch thick. Place the ham, fat side up, in a large roasting pan. Roast in the oven at 325 degrees Fahrenheit until the internal temperature of the meat is 155 F on a meat thermometer.