Beat sugar, butter, salt and vanilla in a stand mixer (using the paddle attachment) or using a hand mixer until light and fluffy.
Add flour, pistachios and cranberries, stir until combined
Divide the dough in half and shape into a log; square, triangle or round.
Roll the log in plastic wrap and then in foil, freeze for at least 1 hour or up to 3 months.
When ready to bake, preheat the oven to 300°F. Lightly grease 2 baking pans or line them with parchment paper.
Remove the cookie logs from the freezer and set them aside for a few minutes to soften a little bit. Then slice them into ¼" thick pieces.
Place them on the prepared baking sheet and bake for 25~35 minutes or until they feel firm. They will not brown much, baking longer at a lower temperature prevent them from darkening.
Remove the cookies from the oven and place them a cooling rack to cool completely. Store them in an airtight container.