Place the spiral ham into the slow cooker, ensuring it fits comfortably.
Whisk together the melted butter and honey, then pour the mixture over the ham, making sure it seeps between the slices.
Cover and cook on low heat until the ham is fully warmed through and tender.
Preheat the broiler and prepare a roasting pan lined with foil.
Mix together the brown sugar, salt, onion powder, garlic powder, and spices in a bowl.
Transfer the ham to the roasting pan and coat the top with half of the sugar mixture, pressing gently so it sticks.
Place under the broiler until the coating becomes golden and bubbly.
Combine the remaining sugar mixture with a small amount of water and heat until it forms a glaze.
Pour the glaze over the ham, slice, and serve warm.