01 -
Heat 1 cup of whole milk in a microwave-safe container until nearly boiling. Whisk in the cocoa powder until fully dissolved and smooth.
02 -
In a 4-quart or larger slow cooker, mix sweetened condensed milk, remaining whole milk, heavy whipping cream, vanilla extract, and semi-sweet chocolate chips. Stir in the cocoa milk mixture prepared earlier.
03 -
Cover and cook on low heat for 2 hours, stirring vigorously at intervals to ensure chocolate chips melt evenly and the mixture is homogeneous and warm throughout.
04 -
Ladle the hot chocolate into mugs and garnish with mini marshmallows or whipped cream and a mini candy cane if desired.