In a large bowl, whisk together the mascarpone, pistachio paste, and vanilla extract.
In another bowl, whip the heavy cream with the sugar until stiff.
Fold the whipped cream carefully into the mascarpone with the crushed pistachios (set 1 tablespoon aside).
Take the ladyfingers and run them through the cooled coffee on one side. Spread half of ladyfingers on the bottom of a baking dish.
Spread half of the cream mixture on top, repeat with another layer of ladyfingers and finish with the cream mixture. You can also add tufts on top, as I did.
Allow the tiramisu to set in the refrigerator for at least 4 hours.
Whip the rest of the cream with the powdered sugar. Carefully spoon in 1 tablespoon of the pistachio paste and decorate the tiramisu with pretty tufts of whipped cream. Garnish with 1 tablespoon of crushed pistachios. Enjoy your tiramisu!