In a slow cooker, combine and stir together: heavy cream, condensed milk, milk, vanilla and chocolate chips.
Cover slow cooker and cook on low for 2 hours. Stir occasionally.
When mixture is hot and chocolate chips are melted, change the setting to warm.
Stir hot chocolate again just before serving. Top with your favorite garnishes and enjoy. We love whipped cream, chocolate drizzles, sprinkles, etc.
Refrigerate any leftovers!