Open the croissants in half with a bread knife.
Dab the inside of the base and top of the croissant with espresso.
Use an electric mixer to whip the mascarpone cheese, whipping cream and icing sugar until they thicken.
Transfer the mascarpone cream to a piping bag and fill the croissants. I also added details to the top of the croissants with it.
Dust the croissant with cocoa powder and grated dark chocolate.