In your mixer bowl (or food processor) cream together the butter, sugar, salt and vanilla extract, scraping down as needed.
Add the flour and mix until incorporated, scraping down as needed.
Mix in the chocolate chips and pistachios until incorporated. Your dough will look sort of sandy, but should stick together when you use your fingers to squeeze it. (At this point you can add a few drops of water here to help it bind – just add 1/2 tsp at a time while mixing or pulsing until it just starts coming together.)
Use your hands to press and roll the dough in to a log, wrap in plastic wrap and refrigerate for at least 60 minutes.
Once the dough is chilled, pre-heat your oven to 375 and line a large baking sheet with a silicone mat or parchment paper. (If you are using a smaller baking sheet you might need two.)
Remove the log from the plastic wrap, slice it in to 1/2 inch slices and place each slice on the prepared baking sheet.
Bake at 375 for 11-14 minutes or until slightly golden around the edges. They will still be soft, but will firm up as they cool.
Let cool on the baking sheet for 10 minutes, then carefully transfer the cookies to a cooling rack. Once completely cooled, you can garnish or just store covered for up to a few days. (Cookies can be frozen to keep longer – if you are going to freeze, don’t garnish with chocolate and nuts until you take them out of the freezer.)