• In a large mixing bowl, add the cold butter and powdered sugar and beat with an electric mixer creamy, scraping down the sides of the bowl a few times.
  1 cup unsalted butter, ½ cup powdered sugar
• Add the vanilla extract and salt and blend to combine in well.
  1 teaspoon vanilla extract, ¼ teaspoon salt
• Gradually add in the flour and stir each addition in with a spatula just until the flour is barely incorporated Be very careful not to over-mix the dough or the cookies will be more dense instead of light.
  2 cups all-purpose flour
• Stir in the chopped pistachios and white chocolate.
  ½ cup pistachios, ½ cup white chocolate
• Divide the dough into two equal portions and shape each into a log about 6 inches long and 1 ½ to 2 inches in diameter., pressing as you roll to remove as many air pockets. Roll on a lightly floured surface if necessary to smooth the shape.
• Wrap each log in plastic wrap or parchment paper and refrigerate for at least one hour to chill before slicing.
• Preheat the oven to 350° F and line a baking sheet with parchment paper.
• Remove the cookie dough from the refrigerator and slice each log into ½ inch thick cookies and place them on the cookie sheet.
• Bake for 8–10 minutes until the edges are lightly golden.
• Place the dough back in the refrigerator between batches so it stays cold.
• After baking, place them to a wire rack to cool completely.

Make the ganache drizzle, if using.

• Add the chopped white chocolate and cream to a microwave safe bowl and heat in the microwave for 30 seconds. Stir and repeat for another 30 seconds. Repeat one more time if needed but be very careful to not overheat it or it will seize and not be usable. (you can also use a double boiler on the stovetop)
  2 ounces white chocolate, 2 tablespoons pistachios, 1-2 tablespoons heavy cream
• Drizzle the ganache over cooled cookies and top with finely chopped pistachios if desired.