Heat the cream to the boiling point. Remove from the heat and add the chopped chocolate, stirring until it is completely melted. Let cool to body temperature, approximately 98°F(36°C), then stir in the vanilla, butter, and mocha paste.
Wait until the filling starts to thicken, then transfer it to a pastry bag with a No. 6 (12-mm) plain tip. Pipe out in small mo