1. In a mixing bowl, beat together butter and sugar until fluffy. Stir in egg and vanilla. Add flour, cocoa powder, salt, espresso and cinnamon; blend until just combined, scraping sides of bowl as necessary.
2. Transfer dough to a square of parchment, form into a log 2 inches in diameter and roll tightly in parchment. Refrigerate until solid, about 1 hr, rotating ever 20 min to maintain shape.
3. Heat oven to 350 degrees F. Place sprinkles in a rimmed pan and roll log in sprinkles until coated well. Slice log into rounds that are slightly less than 1/4 inch thick. Place on parchment-lined baking sheets.
4. Bake until cookies are set and there is slight resistance when you lightly touch centers, 9 to 10 min. Allow to cool completely on the parchment. Store airtight up to 1 week. Makes 40 cookies.