Stiffly whisk the egg whites in a bowl until they form peaks. In a different bowl, beat the egg yolks and confectioner’s sugar together until pale and fluffy. Gently fold the mascarpone cheese into the yolk mixture, then slowly fold in the egg whites, making sure that all the ingredients are well blended but still fluffy.
Mix the coffee, Frangelico, and rum in a flat-bottom pan. Dip each ladyfinger completely into the coffee mixture and then arrange on the bottom of a deep, rectangular serving dish.
Spread a layer of mascarpone cream over the ladyfingers and then sprinkle cocoa powder over the top. Repeat this layering process until the dish is full, and finish with a dusting of cocoa powder.
Using a fine grater, grate chocolate bar over the top of cake.
Cover with plastic or foil, making sure not to get the plastic stuck to the top of cake. Chill for three or more hours before serving.
Jessica Conant-Park
