Break up the chocolate squares and add the slow cooker. Add the remaining ingredients (except the Baileys).
Cover and cook on HIGH for 1.5 hours stirring every 30 minutes.
After the cocoa is hot, stir in the Baileys Irish Cream.
Place mugs, whipped cream and a bowl of marshmallows on the side of the slow cooker for everyone to serve themselves.
Set the slow cooker to warm for your party. This can keep warm for up to 3 hours without issues. Be sure to stir often though.
Video
Notes
Can I serve the Baileys on the side?The Baileys Irish Cream can be left out and set on the side if you have kids or others at the party that will have hot chocolate without.Can I use a flavored Baileys Irish Cream?Yes! Use one of these choices if your store carries them.