Begin by whisking the cold mascarpone cheese on medium speed for 30 to 60 seconds until it becomes smooth and creamy. Set it aside. In a separate heatproof bowl, combine the egg yolks and sugar. Bring 1 to 2 inches of water to a gentle boil in a saucepan, then reduce the heat to the lowest setting. Place the bowl of yolks and sugar over the saucepan, ensuring the bottom of the bowl does not touch the water. Whisk the mixture on medium-high speed for exactly 2 minutes, then remove it from the heat. Pour the warm egg yolk-sugar mixture into the mascarpone cheese. Add the vanilla and a pinch of salt, and whisk on medium speed just until everything is incorporated—do not overmix, as this can make the mixture grainy. In a separate bowl, whip the cold heavy cream until stiff peaks form, being careful not to overbeat. Fold the whipped cream into the mascarpone mixture in 2 to 3 additions using a rubber spatula, gently folding to retain as much air as possible for a light and airy texture.

Start by whisking the cold mascarpone cheese on medium speed for 30 to 60 seconds until smooth and creamy. Set it aside. In a separate heatproof bowl, add the egg yolks and half of the sugar. In a saucepan, bring 1 to 2 inches of water to a gentle boil and lower the heat. Place the bowl over the saucepan, making sure the bottom of the bowl does not come into contact with the water. Whisk the mixture on medium-high speed for exactly 2 minutes, then remove from the heat. Pour this egg yolk mixture into the mascarpone, then add vanilla and a pinch of salt. Whisk just until combined—be cautious not to overmix. In another clean bowl, add the egg whites and the remaining sugar. Place this bowl over the saucepan of simmering water and whisk until the mixture reaches 160°F. Remove from heat and continue whisking until a glossy meringue with stiff peaks forms. Fold the meringue into the mascarpone mixture in 2 to 3 additions, gently incorporating it with a rubber spatula to keep the mixture light and airy.

Pour the prepared coffee into a shallow, wide bowl. Working one at a time, dip each ladyfinger briefly into the coffee—just a quick dip on each side, or up to 1 to 2 seconds per side if you prefer a softer texture. Arrange a layer of dipped ladyfingers on the bottom of a 7x11-inch rectangular dish. Spread half of the mascarpone cream mixture evenly over the ladyfingers. Add a second layer of dipped ladyfingers and top with the remaining mascarpone cream. You can spread it evenly or pipe it on in decorative dollops for a more elegant look. Cover the tiramisu tightly and refrigerate for at least 4 hours, or ideally overnight, to let the flavors develop and the dessert firm up. When ready to serve, sift a generous layer of cocoa powder over the top using a fine mesh sieve. Slice into squares and serve chilled.