In a large mixing bowl, whisk together the egg yolks and sugar until the mixture becomes pale and thick, about 2-3 minutes.

Add the mascarpone cheese to the egg mixture and whisk until smooth and fully combined.

In a separate bowl, beat the heavy cream and vanilla extract until stiff peaks form.

Gently fold the whipped cream into the mascarpone mixture, taking care not to deflate the whipped cream.

In a shallow dish, combine the cooled coffee and coffee liqueur (if using).

Briefly dip each ladyfinger into the coffee mixture, ensuring they remain firm.

Arrange a layer of soaked ladyfingers at the bottom of a 9×13-inch dish or a similar-sized serving dish.

Spread half of the mascarpone mixture over the ladyfingers.

Add another layer of dipped ladyfingers on top of the mascarpone mixture, followed by the remaining mascarpone mixture.

Smooth the top layer with a spatula and cover with plastic wrap.

Refrigerate for at least 4 hours, preferably overnight, to allow flavors to meld.

Before serving, dust the top with unsweetened cocoa powder.