Preheat oven to 250F.

Place the ham cut side down inside the roasting bag and place on the rack in the roasting pan.

Using your fingers, lightly separate the pieces that are spiral sliced.

Place the honey and vinegar in a microwave safe cup and warm until the honey is runny.

Spoon the mixture over the ham, allowing it to run into the slices.

Seal the bag with the twistie they provide, and place ham in the oven on a lower rack.

Bake the ham for 2 hours, 45 minutes (or 12-15 minutes per pound), then remove from the oven.

Remove the roasting bag, and reserve the pan juices.

Place the ham on its side and cover the cut side with a piece of foil.

Stir together the powdered honey and sugar.

Drizzle 1/4 cup reserved pan juices over the slices along with 2 tablespoons melted butter.

Sprinkle 1/3 of the honey/sugar mixture over the ham using your hand to shield on the sides as you sprinkle so it doesn't fall off; pat down lightly.

Continue to bake with the cut side covered and the rest uncovered for 15 minutes.

Remove ham from oven and apply 2 more tablespoons butter and another third of the honey-sugar.

Return to oven, baking 15 minutes more.

Remove ham from oven and set oven to broil/high, lifting the oven rack so the ham with be closer to the element.

Apply the last of the meted butter and honey-sugar.

Remove pan from the oven; drizzle lightly with a little bit of pan juices, the cover all with foil and allow the ham to rest until serving, 15-30 minutes.