Ham with Cherry Port Sauce

Thanksgiving weekend was an orgy of food for us, which is saying something given that we had been in Rome the week before!
Ham is one of my favorite poet-turkey meals, and we served this with a traditional macaroni and cheese as well as non-traditional sides like eggplant with chickpeas and pomegranate molasses and roasted asparagus.

1 spiral-sliced, bone-in ham (7 to 10 pounds)
1 large oven bag (plastic)
3/4 cup ruby port
3/4 cup cherry preserves
1-1/2 cup packed dark brown sugar
1-1/2 teaspoon ground black pepper

1. It is important that you do not unwrap your ham. Leave it fulled wrapped in plastic, but remove any outer wrapping (such as plastic mesh). Discard any glaze that comes with your ham, after reading the list of ingredients so that you understand how disgusting it would be to actually use it.
2. Put wrapped ham in a large tub (or small ice chest) and fill hot tap water. Allow to sit for 45 minutes. Drain the water and fill with more hot tap water, and allow to sit for another 45 minutes. This will allow the ham to gently come up to temperature, and significantly reduce the amount of time that the ham spends in the oven.
3. Set an oven rack to the bottom of your oven and pre-heat to 250-degrees. Unwrap the ham and remove the plastic disk covering the bone from the bottom of your ham. Put in an oven bag, and close the bag snugly over your ham. Put ham in a roasting pan (or Pyrex casserole) cut-side-down. Use a paring knife to make four 1″ slits in the top of the bag, which will prevent the bag from inflating (and popping) during baking.
4. Bake for about 10 minutes per pound (e.g. 11-pound ham took 110 minutes). The center of the ham should reach 100-degrees; measure only in spiral slices, not the unsliced top portion. Remember the ham was fully cooked at the factory, you are only re-heating it; not re-cooking it.
5. With 20 minutes cooking time remaining, put small saucepan over medium burner and reduce 3/4 cup port to 3 tablespoons; about 10 minutes. Add the remaining ingredients and continue cooking over medium heat for 10 more minutes; until it reduces to 1-1/2 cup.
6. Remove ham from oven, and increase your oven to 350-degrees. Cut the oven bag open and roll down the sides to that the ham is exposed, and brush the ham evenly with 1/3-cup of the glaze. Bake for 10 more minutes.
7. Remove ham from oven bag, reserving the juices to loosen the glaze. Again, brush the ham evenly with another 1/3-cup of the glaze. Loosely tent with aluminum foil and allow to rest for 15 minutes.
8. Add 1/2-to-3/4 cup of the ham juices to the remaining glaze. Place over medium burner until it becomes a thick sauce.
9. Carve your ham, serving with the sauce passed separately.