In a bowl or container, combine coffee and coffee liqueur. Set aside.
In a separate bowl, whisk mascarpone, cream, egg yolk, sugar and vanilla seeds together until all is well mixed and you get stiff peaks and a moose like consistency . Set aside.
Dip the biscuits in the coffee mix and line the dish, pour over the creamy mixture and spread evenly all over.
Dust with cocoa powder. Can be eaten immediately or stored in the fridge until required.