6-7 lb cooked, bone-in, butt portion ham
1 cup loosely packed dark brown sugar
¾ cup fresh orange juice
¾ cup Creole or other spicy whole grain mustard
½ cup dark molasses
3 Tbs horseradish
½ tsp allspice
½ tsp cayenne
1. Rinse the ham under cold running water. Pat dry and place on a work surface. With a sharp knife, score parallel lines, 1-inch apart and ¼ -inch deep, across the rounded, skin side of the ham. Turn the ham 180 degrees and score in a similar fashion to create a grid pattern across the ham. Put the ham in a two-gallon plastic storage bag.
2. Combine the remaining ingredients in a large mixing bowl, whisking to mix. Pour the mixture into the bag with the ham and seal. Gently squeeze the bag to evenly distribute the marinade around the ham. Refrigerate for 24 hours.
3. Preheat the oven to 350. Remove the ham from the bag and reserve the marinade. Set the ham, score side up on a rack in a large roasting pan. Bake for 45 minutes.
4. Pour the marinade into a medium saucepan and bring to a gentle boil over medium-high heat. Reduce the heat to low and simmer, uncovered, until it has thickened and will coat the back of a spoon, about 20 minutes.
5. Remove the ham from the oven and evenly baste all sides with the marinade. Return to the oven and bake for an additional 1 ½ – 2 hours, removing every 15 minutes to baste with marinade. Remove from the oven and allow to stand for at least 15 minutes before carving.