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

In a large mixing bowl, beat the mascarpone cheese, heavy cream, sugar, and vanilla extract together until soft peaks form.

Quickly dip each ladyfinger into the coffee mixture, ensuring they are soaked but not soggy. Lay them in a single layer in a 9x9-inch dish.

Spread half of the mascarpone mixture over the layer of ladyfingers.

Repeat the process with another layer of dipped ladyfingers and the remaining mascarpone mixture.

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

Before serving, dust the top with cocoa powder and sprinkle with grated dark chocolate.