01 -
Add milk, heavy cream, cocoa or cacao powder, sugar, vanilla, espresso powder, cinnamon, and salt to a slow cooker.
02 -
Whisk the ingredients together to combine well.
03 -
Stir in the semi-sweet chocolate chips.
04 -
Cover and cook on low for 2-3 hours, stirring occasionally, until the chocolate is fully melted and the mixture is smooth.
05 -
Switch the slow cooker to the warm setting for serving, and stir before ladling into mugs.