Combine cranberries, water, and honey in a medium saucepan. Set over medium heat.
Stir occasionally for about 4-5 minutes, until most of the cranberries have popped.
Add dijon mustard, vinegar, brown sugar, and cayenne pepper.
Continue to cook for another 3-5 minutes until the sauce has thickened some and is syrupy. Remove from heat.
If you have an immersion blender, use it to puree the sauce. (If you don’t, transfer the mixture to a regular blender. Leave the top of the blender vented (to allow steam to escape) and cover with a towel. Blend it up until smooth.)
Preheat your oven to 325 degrees F. Prepare a roasting pan with a roasting rack so that the ham doesn’t cook in it’s own juices (you want a nice crispy bottom, no soggy ham bottoms please.)
Place the ham on the roasting rack and use a sharp serrated knife to score the ham diagonally.
Use a brush to coat the ham all over with the cranberry sauce. (You will repeat this process once more about 20 minutes before the ham is done.)
Place the pan in the oven and roast for 1 and 1/2 to 2 and 1/4 hours, or until a thermometer registers 135 degrees F. (About 20-25 minutes per pound). (You don’t need to worry about the temperature too much since the ham is already cooked. You just want to make sure it’s hot all the way through.
20 minutes before you think it will be done, brush with sauce one more time.
Serve the ham with the remaining glaze (Warm it up in the microwave or on the stove since it will be cool by now.)