In a small bowl, stir together butter and honey, then rub over ham, pushing mixture into slices. Cover and cook on low 4-5 hours.
Towards the end of the cooking time, preheat oven broiler on high and line a roasting pan with foil.
In a small bowl, stir together brown sugar, garlic powder, cinnamon, nutmeg, cloves, paprika, and salt. Press half of the mixture into the top of the ham.
Broil until bubbly and caramelized, about 3 minutes, then remove from oven.
Add remaining sugar mixture to a small saucepan and place over medium heat. Add 3 tablespoons of the ham liquid from the slow cooker (or water). Bring to a boil, stirring occasionally.
Let boil 1 minute, then remove from the heat. Brush glaze over ham, then broil once more briefly, just 1-2 minutes.
Let ham rest at least 5 minutes before serving. Enjoy!