Place ham in extra-large pot and cover with water. Bring to a boil over medium heat; reduce heat and simmer for 1 ½ hours.

Preheat oven to 350°F. Drain ham, then pat dry. Transfer to a roasting pan, fat-side up.

Using a paring knife, cut vanilla in half lengthwise and scrape the seeds. In bowl, whisk together vanilla seeds, maple syrup, orange juice, and pepper.

Using a knife, cut diamond-shaped notches about 1/4-inch deep into surface of the fat.

Insert vanilla pieces into diamonds, then brush with some of the maple mixture. Roast for 1 1/2 hours, basting often with the cooking liquid.

A few minutes before removing from the oven, sprinkle ham with maple sugar and roast until caramelized.

To serve, transfer ham to a platter. Strain the juices from the roasting pan and serve with ham.