• Line two baking sheets with parchment paper and set aside.

Make Pistachio-Almond Flour:

• In a high-speed blender or food processor, add the pistachios and the almond flour. Pulse on medium-low in 30-second increments, scraping the sides down between each interval until the pistachios have turned into a flour. Over pulse and it will be too pastey! Set aside.

Cream the Butter and Sugar:

• In a stand mixer fitted with a paddle attachment, or in a medium bowl using a hand mixer, add the butter and granulated sugar. Beat on medium to cream the butter and sugar, scraping down the sides as needed, until the mixture is very pale yellow and fluffy, 2 to 3 minutes. Add the vanilla extract and almond extract. Mix on low until combined.

Make the Dough:

• Add the pistachio-almond flour mixture, arrowroot, and salt. Mix on low until just combined and a dough has formed. The dough will be very soft and tender.

Roll then Coat the Dough:

• In a shallow bowl, add the powdered sugar. Set aside.
• Using your hands, roll the dough into 1/2-tablespoon-sized balls and place them on one of the the prepared baking sheets. You should have about 28 balls.
• Working one at a time, roll the dough balls in powdered sugar until they are totally coated. Shake off the excess and transfer back to the baking sheet. Repeat until all the dough balls are coated.

Freeze the Dough:

• Transfer the sheet to the freezer and chill for 25 minutes. Meanwhile, preheat the oven to 350°F.

Bake the Dough:

• After chilling, bake the cookies in batches. Transfer about half of the dough balls to the other prepared baking sheet, leaving about 2 inches between each. Transfer to the oven and bake on the middle rack for 13 to 15 minutes, until the tops are crackly and slightly golden around the edges. Transfer to a wire rack to cool while you bake the rest of the cookies.