Pour the milk or cream into a 1.5 quart slow cooker.
Add the vanilla, powdered sugar, cake mix and chocolate chips. Whisk to combine.
Turn the slow cooker to HIGH and heat the cocoa for 1 hour, stirring after 30 minutes. Stir in the creme de cocoa.
Continue to cook for an additional hour, stirring after 30 minutes. If you are not serving the hot chocolate right away, reduce the heat to WARM or LOW setting until ready to serve.
Before serving, pour the hot and steamy boozy red velvet hot chocolate into your favorite serving mugs.
Add a generous helping of whipped cream and a sprinkling of colored sugar and/or Valentine sprinkles.