01 -
In a slow cooker, put 2 cups of heavy cream and whisk in cocoa powder until it's a smooth mix.
02 -
Mix in the rest of the cream, chopped chocolate, whole milk, vanilla, and condensed milk.
03 -
Set the slow cooker on low for 3 hours. Stir every 20 minutes to keep anything from sticking.
04 -
Switch the cooker to warm and leave it there for up to 3 hours. Thin it out with extra milk if it's too thick.
05 -
Pour into cups and top off with marshmallows, whipped cream, or crushed candy pieces.