Whisk the cream, mascarpone, marsala and sugar together in a large bowl until combined.

Divide the sponge fingers into two piles, then dip one pile in the coffee (use a shallow bowl or dish to make life easier), turning them so that they are soaked through, then arrange in the bottom of your serving dish.

Spread half of the cream mixture over the coffee-soaked fingers, then grate the chocolate and add most of it to the top. (Save approximately 5g for later.)

Soak the remaining sponge fingers in coffee then place on top of the cream layer, the add the rest of the cream mixture to cover.

Cover with clingfilm and put in the fridge for a few hours (or overnight). To serve, add the remaining grated chocolate and dust with cocoa powder. The tiramisu will keep up for two days - but will probably vanish much sooner!