Preheat oven to 325 degrees F.
Remove the ham from its packaging. Let it rest for 1 hour at room temperature so it's not so cold, which helps it cook more evenly.
Grab a big roasting pan with a rack. Place the ham on top of the rack, flat side down. You can put a sheet of foil under the ham if you'd like (poke a few holes on the foil so the juices flow down).
Add water to the bottom of the pan, about ½ inch. Wrap the pan tightly in aluminum foil. Cook in the oven for 1.5 hours. Note: The trapped steam inside will keep the ham moist.
About 20 minutes before the ham is done, make the glaze. In a saucepan over medium heat, combine all the glaze ingredients and stir to combine. Adjust the flavors to taste as needed. Reduce to low heat, and simmer for 6 to 8 minutes until it’s a bit thickened, stirring often to make sure it doesn't burn. Set aside.
Remove the ham from the oven and remove the foil. Increase the oven temperature to 400 degrees F.
If needed, reheat the glaze to loosen it up so that it's easier to brush. Brush the ham with glaze, including in between the slices. Then return to the oven for about 6 minutes, uncovered. Repeat this step about 2 more times until caramelized and slightly charred around the edges.
Remove from the oven and let sit for 15 minutes before serving. Slice and serve. Enjoy!