- 1 cup all-purpose flour, plus more for dusting
- ¼ cup granulated sugar, plus more for sprinkling
- ½ teaspoons kosher salt
- ½ cup shelled, salted and roasted pistachios, plus extra crushed pistachios for sprinkling
- ½ teaspoons vanilla extract
- 1 stick cold unsalted butter, cut into ¼” pieces
- 10 ounces bittersweet chocolate chips (60% cocoa), divided
In the bowl of a food processor, combine the flour, sugar, salt, pistachios and vanilla, and pulse 10 to 15 times until the pistachios are finely ground.
Scatter the butter pieces in the food processor and pulse until the dough forms a ball, 1 to 2 minutes. Be careful to not overmix the dough.
Turn the dough out onto a lightly floured work surface and shape into a log about 10 inches long and 2 inches in diameter. Tightly cover the log in plastic wrap. Refrigerate for at least 2 hours or up to 5 days. You can also freeze the dough for up to 3 weeks.
Heat the oven to 325 F. Line 2 rimmed baking sheets with parchment paper.
Cut the chilled cookie dough into ½”-thick coins and place them about 2” apart on the prepared baking sheets.
Lightly brush the top of each shortbread cookie with water and sprinkle with sugar. Bake for 15 to 18 minutes, until the cookies are light golden brown on the top and bottom.
Cool the cookies on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
Meanwhile, heat 1 inch of water in a saucepan over medium heat and cover with a glass bowl, setting up a double boiler. Add ⅔ of the chocolate chips to the glass bowl and heat until completely melted, stirring constantly. Take the chocolate off the heat and stir in the remaining chocolate chips until fully melted.
Dip half of each cookie into the chocolate and place them on a sheet of parchment paper. Sprinkle with crushed pistachios and cool completely.
Store the cookies in an airtight container at room temperature for up to 1 week.