01 -
Heat 1 cup of whole milk in the microwave or on the stovetop until very hot but not boiling. Whisk in the cocoa powder until fully dissolved and smooth.
02 -
In a 4-quart or larger slow cooker, combine sweetened condensed milk, remaining whole milk, heavy cream, vanilla extract, and semi-sweet chocolate chips. Stir well.
03 -
Pour the prepared cocoa milk mixture into the slow cooker with the other ingredients and stir to combine.
04 -
Cover and cook on low heat for approximately 2 hours, stirring vigorously every 20-30 minutes to ensure chocolate chips melt evenly and mixture is uniform.
05 -
Ladle hot chocolate into mugs and garnish with mini marshmallows or whipped cream as desired.