Brew the espresso or strong coffee and allow it to cool completely.
In a large bowl, beat the mascarpone, pistachio cream, powdered sugar, vanilla extract, and salt until smooth and creamy.
In a separate bowl, whip the heavy cream to medium-stiff peaks.
Gently fold the whipped cream into the mascarpone mixture until light and fully combined.
Quickly dip each ladyfinger into the cooled espresso for 1–2 seconds.
Arrange a single layer of soaked ladyfingers in the bottom of a 9×13-inch dish.
Spread half of the pistachio mascarpone mixture evenly over the ladyfingers.
Sprinkle with a portion of the chopped pistachios.
Repeat with another layer of dipped ladyfingers, followed by the remaining pistachio cream.
Smooth the top with a spatula.
Cover and refrigerate for at least 6 hours, preferably overnight.
Just before serving, dust lightly with cocoa powder and garnish generously with chopped pistachios.
