01 - Preheat your oven to 350°F. Line a baking sheet with parchment paper.
02 - Finely grind the pistachios in a food processor. Add softened butter and powdered sugar; blend until creamy. Incorporate the egg, vanilla, flour, and salt. Blend until smooth and well combined.
03 - Slice each croissant horizontally, leaving a small hinge so the two halves remain attached.
04 - Lightly brush the inside of each croissant with simple syrup to maintain moisture during baking.
05 - Spread a generous layer of pistachio cream inside each croissant. Close and arrange on the prepared baking sheet.
06 - Spread a thin layer of pistachio cream on top of each croissant. Sprinkle evenly with chopped pistachios.
07 - Bake for 15 to 20 minutes, or until golden brown and the cream is set.
08 - Allow to cool slightly, then dust with powdered sugar before serving.