In 3 1/2 or 4-quart slow cooker, combine first three ingredients and mix well.
Cover; cook on high setting for 30 minutes, stirring every occasionally until chocolate is melted.
Whisk in stir 2 cups of milk until smooth.
Gradually stir in remaining 6 cups milk and vanilla.
Cover and cook on high for 2 hours or until hot.
Before serving, whisk until cocoa is full combined.
To serve, leave in slow cooker and reduce heat setting to low or warm.
Top with your favorite toppings.
Notes
Make More: If you are going to your kids game, make in the Crock pot while you are getting ready and put in an insulated container and give everyone a treat. Booze it Up: For an adult holiday party, prepare as usual and then have a bar with Bailey's, Kahlua, Fireball or your favorite alcohol and your guest can create their own masterpiece. Its all in the Extras: This is great for a kids party so make the crock pot hot chocolate as directed and then add flavored whip creams, candies, and syrups and let the kids have a ball.