Flour mixture: In a small mixing bowl, stir together the flour and salt. Set aside.
Butter mixture: In a large mixing bowl, add the softened butter. Use an electric hand mixer to beat the butter until it becomes very creamy and slightly pale in colour. Add the granulated sugar, powdered sugar, and vanilla extract. Beat together until creamy.
Combine: Add the flour mixture to the butter mixture. Mix on low speed until just barely combined, still a bit floury. Add the finely chopped dried cranberries and pistachios. Mix on low speed until the dough comes together. It will look too dry at first but just keep mixing and it will start to clump together and will hold together when squeezed.
Shape dough: Turn the dough out onto a a sheet of plastic wrap. Press the dough together with your hands and roll and shape it into a log shape that's about 12" long and 2" in diameter. You can split it in half to make two 6" logs if that's easier for you.
Chill dough: Wrap the log in plastic wrap and chill in the fridge for at least 4 hours or overnight, preferably. If you can, stand the log up on one end so that one side doesn't get flattened.
Prep: Preheat the oven to 350°F. Line a baking sheet with parchment paper and set aside.
Slice: Once chilled and firm, use a sharp knife to cut the log into ½" coins. If any pieces break off, you can easily press the dough back together. Place the cookie dough coins on your lined baking sheet. They will only spread slightly but I still like to leave ½-1" in between each cookie.
Bake: Bake cookies for about 15 minutes or until the bottom edges just start to become lightly golden brown.
Cool: Let the cookies cool on the baking sheet for about 10 minutes before transferring them to a wire rack to cool completely.