01 -
In a stand mixer fitted with the paddle attachment (or a large bowl with hand mixer), combine the butter, powdered sugar, vanilla, and salt. Beat on medium-low until combined and creamy, about 1 1/2 minutes.
02 -
Add the flour and pistachios, and mix until just combined and the dough starts to clump together, about 2 minutes.
03 -
Turn the dough out onto a cutting board and form into a flat disc. Cut the dough in half and shape each half into a 23cm long log. Wrap each log in plastic wrap and freeze for 30 minutes until firm.
04 -
Preheat your oven to 180°C (350°F).
05 -
Remove the dough from freezer and unwrap. Brush each log with beaten egg, then roll in the coarse sugar, coating the sides evenly.
06 -
Using a sharp chef's knife, cut the dough into 8mm thick slices. Place cookies on a baking sheet lined with parchment paper or a silicone baking mat. Allow about 20 cookies per standard baking sheet as they don't spread much during baking.
07 -
Bake for 18-20 minutes, rotating the baking sheet 180° halfway through for even browning. Bake sheets one at a time for best results.
08 -
Let the cookies cool completely before eating to achieve their perfect buttery, crumbly texture. Store in an airtight container for up to 4 days.