Beat egg whites until stiff white peaks. In a separate bowl, beat egg yolks and sugar until creamy and lemon colored. Add marscapone cheese to egg yolk mixture, beat until smooth. Then fold in the egg whites. Soak the ladyfingers in the coffee, and make a layer of half of them. (I found quickly dipping each ladyfinger in the coffee worked well) Cover layer of ladyfingers with half the cheese. Repeat layer of ladyfingers and layer of cheese. Mix together about 2 tsp of cocoa with 2 tsp powdered sugar, and sift over the top. Cover and refrigerate.