Preparation

1. Stir together flour, cinnamon and salt in a bowl.
2. Beat together butter, sugar and zest in a large bowl with an electric mixer at medium-high speed until pale and fluffy, about 3 minutes.
3. Reduce speed to low and add flour mixture in 3 batches, mixing until dough just comes together in clumps, then mix in pistachios and cranberries.
4. Gather and press dough together, then divide into 2 equal pieces.
5. Using a sheet of plastic wrap or wax paper as an aid, form each piece of dough into a log about 1 ½ inches in diameter.
6. Square off long sides of each log to form a bar, then chill, wrapped in plastic wrap until firm, at least 2 hours.
7. Put oven racks in upper and lower thirds of oven, preheat to 350°.
8. Line baking sheets with parchment paper.
9. Brush egg over 4 long sides of bars, sprinkle decorative sugar on separate sheet of wax paper and press bars into sugar.
10. Cut each bar crosswise in ¼ inch thick slices. Arrange cookies about ½ inch apart.
11. Bake cookies, switch positions halfway through baking, until edges are pale golden about 15-18 minutes. Transfer cookies to racks to cool.