Coffee Custard Sauce
Heat the cream in a saucepan over medium heat until bubbles form around the edges, 6 to 8 minutes. Add the chocolate and butter. Remove the pan from the stove and stir until the chocolate and butter have melted. Transfer the mixture to a blender and blend until very smooth, 1 minute.
Combine the milk, cream and vanilla bean in a medium saucepan. Heat over medium heat until bubbles form around the edges, 6 to 8 minutes.
Beat the sugar and yolks together in a medium bowl until thick, 2 to 3 minutes. Pour about half the milk mixture into the eggs, stirring constantly. Return the mixture to the saucepan and cook, stirring until the sauce thickens slightly, about 3 to 4 minutes.
Strain the Vanilla Sauce into the Chocolate Sauce. Stir in the ground coffee.