Step 1: Prepare the Egg Mixture

The base of the mascarpone cream starts with a cooked egg yolk mixture.

1. In a large heatproof bowl, combine the egg yolks, sugar, and salt.
2. Place the bowl over a saucepan of simmering water (double boiler method). The bottom of the bowl should not touch the water.
3. Whisk continuously until the mixture thickens, turns pale in color, and reaches 165°F-170°F. This process takes about 10-13 minutes and ensures food safety.
4. Remove the bowl from heat and allow the mixture to cool for 5-10 minutes.

Step 2: Incorporate Mascarpone and Whipped Cream

1. Gently whisk the cold mascarpone cheese and vanilla extract into the cooled egg mixture. Avoid overmixing, as mascarpone can become grainy.
2. In a separate bowl, use a hand mixer to beat the heavy cream to medium-stiff peaks. This means the cream holds its shape but slightly curls at the tip.
3. Fold half of the whipped cream into the mascarpone mixture using a spatula, then gently fold in the remaining whipped cream. Set aside.

Step 3: Soak the Ladyfingers

1. In a shallow dish, mix the espresso and coffee liqueur (if using).
2. Quickly dip each ladyfinger into the coffee mixture for about 1 second per side. Over-soaking will make them mushy, so a quick dip is best.
3. Arrange half of the soaked ladyfingers in a 9×13-inch baking dish, forming an even layer.

Step 4: Assemble the Layers

1. Spread half of the mascarpone mixture over the first layer of ladyfingers.
2. Add another layer of dipped ladyfingers on top.
3. Spread the remaining mascarpone mixture evenly over the second layer of ladyfingers.

Step 5: Finish and Chill

1. Dust the top generously with unsweetened cocoa powder using a fine sieve.
2. Cover the dish with plastic wrap and refrigerate for at least 8 hours, preferably overnight. This allows the flavors to meld and the texture to set.a