In a mixing bowl, whisk together the mascarpone cheese, heavy cream, pistachio paste, powdered sugar, and vanilla extract until smooth and creamy.

Set aside in the refrigerator to chill while preparing the coffee mixture.

In a shallow dish, combine the brewed coffee and coffee liqueur, if using. Stir to mix well.

Quickly dip each ladyfinger into the coffee mixture, ensuring they are soaked but not soggy.

Layer half of the soaked ladyfingers in the bottom of a 9x9 inch baking dish.

Spread half of the pistachio cream over the ladyfingers.

Repeat with another layer of soaked ladyfingers and the remaining pistachio cream.

Cover and refrigerate for at least 4 hours, preferably overnight, to set.

Before serving, garnish with chopped pistachios and dust with powdered sugar if desired.

Slice and serve chilled.