In a large pot combine all of the ingredients over low heat. Keep mixture over low heat for 30-40 minutes whisking occasionally until chocolate is fully melted and incorporated with the other ingredients. You can add milk here to adjust to your chocolate preference. Give it a good whisking before serving to get it nice and frothy. If you have an immersion blender, that works great here.
Serve immediately or pour into a crockpot and keep warm until ready to serve.
Top with whipped cream, crushed candy canes, or sprinkles.