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

In a large mixing bowl, whip the heavy cream until soft peaks form.

In another bowl, mix the mascarpone cheese, granulated sugar, and vanilla extract until smooth and creamy.

Gently fold the whipped cream into the mascarpone mixture until fully combined.

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

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

Dust half of the cocoa powder over the mascarpone layer.

Repeat the process with another layer of dipped ladyfingers, the remaining mascarpone mixture, and the rest of the cocoa powder.

Cover and refrigerate for at least 4 hours, preferably overnight, to allow the flavors to meld.

Before serving, garnish with grated dark chocolate.