- In a coffee mill, finely grind the beans.
- In a coffee maker, brew the espresso with the boiling water.
- Meanwhile, in a small bowl, combine the sugar and cinnamon and set aside.
- Using a small knife, scrape the seeds from the vanilla bean into a medium saucepan.
- Pour in the milk and scald over moderate heat, about 5 minutes.
- Remove from heat, add chocolate and stir until melted.
- Cover and keep warm over very low heat.
- Divide the hot espresso into 4 cups.
- In a blender, begin whipping half of the warm chocolate milk at low speed.
- Gradually increase the speed to high and blend until frothy, about 1 minute.
- Pour the chocolate milk into the cups of coffee, stir briefly and top each serving with some of the milk froth.
- Sprinkle the reserved cinnamon sugar on top.
- Serve immediately with a dollop of whipped cream, if desired.