Icebox cookies get their name from the fact that the dough must be chilled first, before being sliced into individual cookies. These are flavored with cocoa powder and finely ground black pepper.
In a large bowl, sift together the flour, cocoa powder, salt pepper, espresso, and cinnamon; Set the flour mixture aside.
In the bowl of a electric mixer fitted with the paddle attachment, beat together the butter and sugar until light and fluffy. Add the egg and vanilla; beat to combine. Add the reserved flour mixture, beating on low speed, until combined.
Have ready a large piece of parchment paper. Turn out the dough onto parchment, and roll into a 2-inch diameter log. Roll log in the parchment. Transfer log to the refrigerator, and chill dough at least 1 hour overnight.
Heat the oven to 375 degrees. Line 2 baking sheets with parchment paper. Remove the log from refrigerator, and remove the parchment. Pour the sanding sugar onto a baking pan, and roll the log in the sugar, gently pressing down to adhere sugar to dough. Transfer the log to a cutting board, and slice it into 1/4 inch-thick rounds. Place the rounds on the prepared baking sheets, spacing 1 inch apart. Sprinkle each cookie with some freshly ground black pepper.
Bake the cookies until there is slight resistance when you light touch them in the centers, about 12 minutes. Transfer cookies to a wire rack to cool completely. Bake remaining dough. Store cookies in airtight container up to 2 days.
Sanding sugar, which has larger crystals than granulated sugar, makes a more decorative topping on the baked cookies; however, you can also use granulated sugar.