To prepare mascarpone cheese, add vinegar or lemon juice to the fresh cream. Heat till the cream becomes thick with small flecks. Drain and hang in muslin cloth for atleast two days.
To prepare tiramisu, take egg yolks in a bowl and whip them with icing sugar. Add mascarpone, mix well and let it rest for five minutes.
Now gently fold in the whipped cream. In a separate bowl, mix sweet rum with espresso coffee and sugar. Keep aside.
Arrange the pieces of sponge cake in a dish. Soak them with coffee mixture. Spread the mascarpone mixture on top followed by another layer of sponge cake. Soak it again with the coffee mixture. Add another layer of mascarpone. Dust it generously with cocoa powder and refrigerate for half an hour.
Serve the Tiramisu chilled!
Tiramisu is an Italian cake and dessert. Plump cake soaked in coffee and rum, topped with cream and ricotta cheese mixture, sprinkled with bitter chocolate and cocoa powder.