Preheat oven to 375 degrees F. Line cookie sheets with parchment paper.
In a small bowl, mix spices together. Reserve 1/4 tsp of spice mixture for glaze.
In a separate bowl, mix together flour, salt. Add in unreserved spice mixture.
In a large bowl, cream together butter, sugar, and vanilla. Add in flour mixture and beat until ingredients are just combined. (Dough will still be crumbly.) Stir in 1/4 cup pistachios. With your hands, continue mixing and press dough together until it forms a ball.
Divide dough in half. Transfer one half to lightly floured surface and press (or gently roll) into 1/4" thick rectangle. Cut with round (or other shape) cookie cutter and use a knife or spatula to place cookies about 1" apart on prepared cookie sheet. Repeat with other half of dough.
Bake 10 minutes, or until lightly browned on edges. Cool 2-3 minutes on cookie sheets and then carefully transfer to cooling rack.
Mix together powdered sugar, vanilla, reserved 1/4 tsp spice mixture and milk, adding a little more milk if necessary to get desired consistency (thick but spreadable).
When cookies are cool, spread a thin layer of glaze on about half the cookie. Cover that half with chopped pistachios. Let stand until glaze/pistachios are set.