Directions

1. Sift together flour, cocoa powder, salt, pepper, espresso powder, and cinnamon into a large bowl; set aside.
2. Put butter and granulated sugar in the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until pale and fluffy, about 3 minutes. Mix in egg and vanilla. Reduce speed to low. Add flour mixture; mix until just combined.
3. Turn out dough onto a piece of parchment paper, and roll into a 2-inch-diameter log. Roll log in the parchment. Refrigerate at least 1 hour or overnight.
4. Preheat oven to 350 degrees. Remove log from parchment paper. Let soften slightly at room temperature, about 5 minutes. Roll log in sanding sugar, gently pressing down to adhere sugar to dough. Transfer log to a cutting board, and slice into 1/4-inch-thick rounds. Place rounds on baking sheets lined with parchment paper, spacing 1 inch apart. Sprinkle each round with freshly ground pepper.
5. Bake cookies until there is slight resistance when you lightly touch centers, about 10 minutes. Transfer cookies to wire racks to cool completely. Cookies can be stored in airtight containers at room temperature up to 2 days.