Start to Finish Time:
In the large bowl of an electric mixer, cream together butter, ½ cup sugar, and salt. Beat in egg yolk; mix well. Add flour and pistachios; blend on low speed until just combined. Remove dough from mixer and, with a strong spoon or your hands, mix in cherries. Divide dough in half and roll each piece into a log about 12 inches long; wrap in plastic and chill overnight.
Adjust the oven rack to the center shelf and preheat to 350°. Line a cookie sheet with parchment paper (or grease lightly); set aside. Pour coarse sugar onto a piece of waxed paper or aluminum foil. Lightly brush egg white over the surface of the log; press and roll log into sugar; transfer to a cutting board. Using a sharp knife, slice log in ½-inch slices; transfer to cookie sheet and bake 12 to 15 minutes. Cool completely and store in an airtight container or freeze.