Add all ingredients for the hot chocolate to a crockpot and whisk until combined.
Cover and cook on low for 2 hours, stirring every 20-30 minutes or so to keep the chocolate chips from settling at the bottom. Crockpots all are a little different when it comes to temperatures so keep an eye on it to make sure the chocolate doesn’t burn. You’ll want the temperature to reach anywhere between 160-185 degrees F.
After 2 hours, whisk before serving. Serve with marshmallows on top!