1 shank-end, spiral-sliced, bone-in ham, 6 to 8 pounds
1/2 cup maple syrup
1/2 cup dark mollasses
2 tablespoons whole grain mustard
1/4 teaspoon ground cinnamon
Adjust oven rack to lower position and preheat oven to 250?F. Place ham in oven bag or wrap tightly with foil and place on rack set in rimmed gaking sheet. Transfer to oven and cook until ham reaches 120?F in center about 2 1/2 hours.
Meanwhile, combine maple syrup, dark molasses, mustard, and cinnamon in small saucepan. Bring to a boil over high heat, reduce to a simmer, and cook, stirring occasionally until thick and syrupy, about 15 minutes.
When ham has reached 120?F, remove from oven and unwrap. Paint with 1/3 of sauce, increase oven temperature to 400 degrees, and bake 5 minutes. Paint with 1/3 more glaze and bake until crisp and shiny, 10 minutes longer. Remove from oven and paint with remaining glaze. Tent with foil and allow to rest 15 minutes before slicing and serving.