- In heavy-bottomed pot, combine milk and cream. Scrape seeds from vanilla bean into pot and add pod. Set over medium heat until hot.
- Add chocolate, stirring to incorporate until completely melted. Turn heat to low. Add cinnamon and stir.
- Remove vanilla bean. Mixture will thicken as it simmers; take care not to scorch.
- Stir in bourbon, and remove from heat. Serve in mugs and garnish with marshmallows.