01 -
Heat 1 cup of whole milk in the microwave or on the stove until scalding but not boiling. Whisk in ¼ cup unsweetened cocoa powder until smooth.
02 -
In a 4-quart or larger slow cooker, add sweetened condensed milk, remaining whole milk, heavy whipping cream, vanilla extract, and semi-sweet chocolate chips. Stir in the prepared cocoa mixture.
03 -
Cover and cook on low for approximately 2 hours, stirring vigorously every 15-20 minutes to evenly melt the chocolate chips and integrate the mixture.
04 -
Ladle the hot chocolate into mugs and garnish with mini marshmallows or whipped cream as desired.