Let ham sit at room temperature for 1 hour before baking
Preheat oven to 325ºF
Place all of the glaze ingredients in a small saucepan and whisk to combine - Place over medium-high heat and bring to a simmer - Allow to simmer (stirring regularly) for 10 minutes – Remove from heat and allow to cool for 5-10 minutes
Using a sharp knife, score the ham in a diamond pattern ¼ inch deep and ¾ inch apart
Place the ham cut side down on a roasting rack in a roasting pan - Pour the vinegar in the bottom of the roasting pan
Generously brush the ham with apx ⅓ of the glaze - Loosely tent with aluminum foil
Place in the bottom third of the pre-heated oven and roast until an internal temperature of 120ºF is achieved (apx 15 minutes per pound) making sure to stop midway through cooking time to lift the foil and brush another ⅓ of the glaze over the ham
30 minutes before the end of cooking, remove the foil, brush the generously with the remaining glaze (leaving ¼ cup or so for finishing) and finish baking without the foil until internal temperature is 120ºF
Switch oven to broil, allow to cook until slightly charred around the edges - Remove from oven and brush with the remaining marinade - Allow to rest 20 minutes before slicing and serving hot