Classic Tiramisu

Method

1. In a large metal mixing bowl, combine egg yolks, sugar, and Marsala. Place the bowl over a pot of simmering water and cook, whisking, until the mixture becomes pale, thick, and doubles in volume (about 5 minutes). Remove from heat and let it cool completely.
2. In a wide bowl or baking dish, stir together espresso and 5 tablespoons of rum; set aside.
3. Once the egg mixture is chilled, add it to the bowl of a standing mixer fitted with a whisk attachment. Mix for 2 to 3 minutes.
4. Add mascarpone and beat at medium speed until no lumps remain (30 to 45 seconds), scraping down the bowl as needed. Transfer the mixture to a large bowl and set aside.
5. In the now-empty mixer bowl, beat the cold cream at medium speed until frothy (1 to 1 1/2 minutes). Increase speed to high and continue beating until the cream holds stiff peaks (1 to 1 1/2 minutes longer). Fold one-third of the whipped cream into the mascarpone mixture to lighten, then gently fold in the remaining whipped cream until no white streaks remain. Set aside.
6. Working one at a time, quickly dip half of the ladyfingers into the coffee mixture and arrange them in a 13 x 9-inch glass or ceramic baking dish. Spread half of the mascarpone mixture over the ladyfingers. Dust with 2 tablespoons of cocoa using a fine-mesh strainer.
7. Repeat the dipping and arrangement of ladyfingers. Spread the remaining mascarpone mixture over them and dust with the remaining 1 1/2 tablespoons of cocoa. Wipe the edges of the dish with a dry paper towel. Cover with plastic wrap and refrigerate for 6 to 24 hours.