Pistachio Shortbread–Christmas Cookie #1

Pistachio shortbread:

 1 cup unbleached all-purpose flour, plus more for the work surface

 1/4 cup granulated sugar

 1/2 teaspoon kosher salt

 1/2 cup shelled raw or roasted pistachios

 1/2 teaspoon vanilla extract

 1 stick (4 ounces) unsalted butter, cold, cut into 1/4-inch pieces

 1 to 2 tablespoons granulated sugar, sanding sugar, or raw sugar, for garnish

1. Pulse the flour, granulated sugar, salt, pistachios, and vanilla in the bowl of a food processor for 1 to 2 minutes, until the pistachios are finely ground. Scatter the butter pieces in the food processor and pulse several times to cut the butter into the flour. Stop pulsing when the ingredients just come together and cling to one another. (Watch carefully, as food processors work very fast and can easily overmix the dough. At first the mixture will have a coarse, crumbly texture, but then if…