Preparation Combine milk, 1/2 cup cream, sugar, salt, and 1/4 cup water in a large heavy saucepan. Scrape in seeds from vanilla bean; add bean. Bring to a boil, stirring to dissolve sugar. Add chocolate and cocoa powder; whisk until chocolate melts and mixture just comes to a boil. DO AHEAD: Cocoa can be made 1 day ahead. Let cool; cover and chill. Bring to a simmer before continuing. Whisk remaining 1/2 cup cream and ground coffee in a small bowl until firm peaks form. DO AHEAD: Whipped cream can be made 2 hours ahead. Cover and chill. Rewhisk if needed before using. Remove vanilla bean from hot cocoa; discard. Transfer cocoa to a blender and purée until thick and foamy, about 2 minutes. Scoop ice cream into teacups; pour hot cocoa into cups, dividing evenly. Top each with a small dollop of coffee whipped cream. Garnish with a small candy cane, if desired.
Preparation Combine milk, 1/2 cup cream, sugar, salt, and 1/4 cup water in a large heavy saucepan. Scrape in seeds from vanilla bean; add bean. Bring to a boil, stirring to dissolve sugar. Add chocolate and cocoa powder; whisk until chocolate melts and mixture just comes to a boil. DO AHEAD: Cocoa can be made 1 day ahead. Let cool; cover and chill. Bring to a simmer before continuing. Whisk remaining 1/2 cup cream and ground coffee in a small bowl until firm peaks form. DO AHEAD: Whipped cream can be made 2 hours ahead. Cover and chill. Rewhisk if needed before using. Remove vanilla bean from hot cocoa; discard. Transfer cocoa to a blender and purée until thick and foamy, about 2 minutes. Scoop ice cream into teacups; pour hot cocoa into cups, dividing evenly. Top each with a small dollop of coffee whipped cream. Garnish with a small candy cane, if desired.