Cranberry Pistachio Shortbread Cookies

0 In a large bowl, cream together the softened unsalted butter, powdered sugar, vanilla extract, and salt until light and fluffy (about 2 to 3 minutes).
1 Add the all-purpose flour a ½ cup at a time until all the flour is added. Then mix in the finely chopped cranberries and pistachios. Stop mixing when the dough becomes a medium sized pebble like texture (about 2 to 3 minutes).
2 Using your hands, work the dough into a smooth ball then divide into 2 equal pieces. 
3 On top of plastic wrap, use it to help roll and form each piece into a 2 inch diameter log and 7 to 8 inches long with flat ends. Wrap the log tightly in the plastic wrap and freeze* for 1 hour.*ELIZABETH'S NOTE: Or refrigerate for at least 2 hours and up to 3 days.
4 Preheat oven to [wprm-temperature value="350" unit="F"]. Line 2 baking sheets with parchment paper and set aside.
5 On a small plate, stir together the finely chopped pistachios and sanding sugar.
6 Remove logs from the freezer and unwrap. Cut each log with a very sharp and thick knife into 12 equal pieces (about ½ inch thick).
7 Roll outside of cookies in the pistachio sugar mixture. Place on baking sheet in 3 rows of 4. 
8 Bake for 12 to 15 minutes. The cookies will be pale and the tops will no longer glistened when they have finished baking.
9 Allow them to cool on the baking sheet before transferring to a cooling rack to cool completely.