Heat milk and half and half (if using) in a saucepan over medium low heat just until it starts to simmer. Add chocolate chips and Fireball™ Whiskey Flavored Seasoning. Reduce heat to low and stir frequently until chocolate is melted.
Serve in mugs and top with marshmallows and chocolate chips, and sprinkle with additional Fireball Seasoning.
*For richer hot chocolate, use 1 cup milk and 1 cup half and half.