Turn the slow cooker on low. Add in the sweetened condensed milk with the milk chocolate chips, cocoa powder, granulated sugar, and salt.

Mix until the chocolate chips are melted, then add in the milk. Stir until mostly incorporated and the milk is a light brown color.

Place the lid on the slow cooker and cook on low for 1.5 hours.

Mix a few times during the cooking process to make sure the chocolate chips are fully melted and incorporated into the dairy mixture.

Once hot, mix well and ladle hot chocolate into cups. Garnish with a layer of mini marshmallows, and whipped cream.