Beat the pistachio paste and ¼ cup of the heavy cream with a hand mixer or whisk until smooth. Add the mascarpone, vanilla and salt. Beat until completely smooth.
In the bowl of a stand mixer fitted with a whisk attachment, combine the remaining 1 cup of heavy cream with the granulated sugar. Beat until stiff peaks.
Add the whipped cream to the mascarpone mixture and fold until combined. Set aside.
Assemble the tiramisu
Whisk together the coffee, alcohol (if using) and pistachio flavoring in a shallow dish. Working with half of the ladyfingers, quickly dip each one, one at a time, into the coffee mixture and place them in a single layer covering the bottom of a 9x9-inch square pan. Top with half of the cream mixture, smoothing it out to the edges.
Dip the rest of the ladyfingers into the coffee mixture and create another layer. Top with the remaining cream mixture and smooth the top.
Garnish with pistachio paste (loosened with water if needed) and chopped pistachios*. Chill in the refrigerator until ready to serve, or for at least 2 hours and up to overnight.
Notes
*I warmed up and added a bit of water to some pistachio paste to loosen it before transferring it to a piping bag. I piped lines on top and used a toothpick to drag in opposite directions to create the feathered pattern.This can be made in any shape of baking dish of a similar size.
Nutrition
Serving: 1sliceCalories: 510kcal
Keyword green, ladyfingers, no bake, pistachio, pistachio paste, pistachio tiramisu, pistachios, saint patrick's day, st patricks day, tiramisu