This recipe is from Easy Entertaining with Michael Chiarello on Food Network. You may make this ahead and reheat. Make sure to either whisk it or blend it in a blender to make it light and foamy before serving.
Bring water to a boil in a saucepan. Split the vanilla bean and add to the boiling water. Add sugar, cinnamon, espresso, and a pinch of salt. Simmer for 1 minute and add the bittersweet chocolate. Whisk until it gets thick. Add milk and simmer 1 minute.
Serve immediately with sprinkling of chili powder on top, and you can add a dollop of vanilla ice cream if you wish.