Recipe from Cooking in the Moment: A Year of Seasonal Recipes (Publisher: Clarkson Potter) by Chef Andrea Reusing of The Lantern in Chapel Hill and The Durham in Durham, North Carolina
2 heads of garlic, unpeeled, cut in half crosswise
1 large yellow onion, cut in half
1 tablespoon black peppercorns
1 tablespoon coriander seeds
3 dried bay leaves
1 small bunch of fresh flat-leaf parsley
1 tablespoon expeller-pressed vegetable oil
1 15- to 18-pound fresh ham, skin-on, trimmed
To brine the ham, combine 4 quarts cold water, 1 cup salt, and the garlic, onion, peppercorns, coriander, bay leaves, and parsley in a container that is large enough to hold the ham, and stir until salt is dissolved.
Submerge ham in liquid and refrigerate for at least 24 hours and up to three days. (Alternatively, if you can’t fit the ham in your refrigerator, brine it directly in a clean cooler, just adding a little extra salt and enough ice to keep the ham cold, draining a little brine and adding more ice as needed.)
Preheat the oven to 350 degrees.
Drain ham, discarding all brine and seasonings. Pat ham dry. Put ham on top of a paper towel lined cutting board so that it doesn’t slip. Using a sharp knife, score skin with incisions that run the length of the ham and are about ½-inch apart, and then again the other way to form a crosshatch pattern. Incisions should just barely reach into fat under the skin; do not cut into meat itself, in order to help crackling skin stay in one piece once it is crispy. Allow ham to come to room temperature.
Lightly oil and salt meat, rubbing it in on all surfaces. Place ham on roasting rack or on a few rolled-up sheets of aluminum foil in large heavy roasting pan, and put it in oven. A 15-pound roast will take almost four hours to roast, while an 18-pound ham will take as long as five hours— about 15 minutes per pound. After roasting 2½ hours, when temperature of the ham hits about 130 degrees, raise oven temperature to 425 degrees to crisp the skin (cover any areas that start to get too dark with a piece of foil). When meat thermometer reads 145° to 150°F, remove from oven and allow it to rest, loosely tented with foil, for an hour or so before carving.