In the bowl of a stand mixer fitted with a paddle attachment, or in a bowl with a hand mixer, beat the butter and sugar together on medium high speed until creamy and pale in color, about 4-5 minutes. Add the vanilla extract. Add the flour, pistachios and salt, and mix until just combined.

Shape the dough into rounded tablespoons and place on the prepared baking sheet, about 1 inch apart. Bake until cookies just begin to turn golden brown, about 15 minutes.

Let sit on the pan until cool enough to touch but still warm, then roll in powdered sugar. Let cool completely and then roll in powdered sugar again.

Note: If you use salted pistachios, omit the salt in the cookies.