Brew 1 cup of espresso and let it cool to room temperature. Combine with coffee liqueur and sugar in a shallow dish, stirring until the sugar dissolves.

Quickly dip each ladyfinger into the espresso mixture and arrange them in a single layer at the bottom of a 9x9 inch dish.

In a medium bowl, whisk together egg yolks and granulated sugar until pale and creamy. Fold in mascarpone cheese until well combined.

In a separate bowl, whip heavy cream with vanilla extract until stiff peaks form. Gently fold the whipped cream into the mascarpone mixture.

Spread half of the mascarpone mixture over the layer of soaked ladyfingers. Add another layer of soaked ladyfingers on top, followed by the remaining mascarpone mixture.

Cover the dish with plastic wrap and refrigerate for at least 4 hours, preferably overnight.

Before serving, dust the top with cocoa powder and garnish with dark chocolate shavings if desired.