Begin by softening the unsalted butter to room temperature so it creams easily. Meanwhile, crush the fresh raspberries gently using a fork or potato masher—avoid pureeing to retain some texture. Finely chop the pistachios to a size that will provide crunch without overwhelming the dough.
In a large mixing bowl, beat the softened butter with granulated sugar and powdered sugar until the mixture is light, fluffy, and well combined. This aeration helps create a tender, melt-in-your-mouth cookie.
Mix in the vanilla extract and salt until evenly incorporated. These small additions elevate the flavors and balance the sweetness.
Gradually add the all-purpose flour to the butter mixture, stirring just until combined. Gently fold in the chopped pistachios and crushed raspberries, taking care not to overwork the dough, which could result in tougher cookies.
Turn the dough out onto a lightly floured surface and shape it into a log about 2 inches in diameter. Wrap tightly in plastic wrap and refrigerate for at least 1 hour. Chilling helps the dough firm up, making it easier to slice and bake without spreading too much.
Preheat your oven to 325°F (165°C). Line a baking sheet with parchment paper or a silicone baking mat. Slice the chilled dough into 1/4-inch thick rounds and place them evenly spaced on the baking sheet. Bake for 15-18 minutes, or until the edges just begin to turn golden.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack. Once cooled, these cookies are ready to be enjoyed with a cup of tea or coffee.