1. Preheat oven to 350°. Make shallow cuts in fat of ham 1 inch apart in a diamond pattern. Rub olive oil and ground pepper over ham. Place ham on a rack in a 14- x 11-inch roasting pan. Pour wine into bottom of pan; stir in peppercorns and next 3 ingredients. Add 4 cups water. Cover pan loosely with aluminum foil.
2. Bake, covered, at 350° on lower oven rack 2 hours.
3. Meanwhile, bring ginger ale to a boil in a deep-sided 12-inch skillet over medium-high heat, and boil 25 to 30 minutes or until reduced to 3/4 cup. Remove from heat, and stir in pepper jelly until smooth.
4. Uncover ham, and bake 2 1/2 more hours or until a meat thermometer registers 160° and ham is caramelized, basting every 30 minutes with ginger ale mixture. (Shield ham with foil to prevent excessive browning.) Remove from oven; transfer to a serving platter, reserving 2 cups pan drippings. Let stand 20 minutes before carving.
5. Pour reserved drippings through a fine wire-mesh strainer into a medium saucepan; skim fat. Bring drippings to a boil over high heat, and boil 12 to 15 minutes or until liquid is reduced to 3/4 cup. Remove from heat; stir in mustard. Serve with ham and Cornmeal-Chive Biscuits.
Note: To prepare a 12- to 14-lb. fully cooked bone-in ham, increase red pepper jelly to 1 cup, olive oil to 2 Tbsp., mustard to 1 1/2 Tbsp., and ground pepper to 2 tsp. Prepare recipe as directed, cooking ginger ale mixture 20 to 25 minutes or until reduced to 1 1/2 cups in Step 3, reserving 3 cups drippings in Step 4, and cooking reserved drippings until reduced to 1 1/2 cups in Step 5. Makes 18 to 24 servings. Hands-on time 15 min.; Total time 4 hours, 55 min.