1 ½ cups all-purpose flour
¾ cup unsweetened cocoa powder
½ teaspoon cinnamon
¼ teaspoon salt
? teaspoon freshly ground black pepper
? to 1/4 teaspoon cayenne pepper
½ cup unsalted butter (1 stick)
1 cup brown sugar
1 large egg
1 teaspoon vanilla extract
Combine the first 6 ingredients in a medium bowl. Mix thoroughly with a whisk and set aside. In a mixing bowl, beat the butter and brown sugar until creamy. Add the egg and vanilla extract and beat on high until fluffy, about 1 minute. Gradually stir the flour mixture into the butter mixture until the butter is just incorporated.
Turn the dough out onto wax paper. Use the paper to shape and roll the dough into a cylinder about 10 inches long and 1 1/2 to 2 inches in diameter. Wrap tightly in more wax paper, folding or twisting the ends to seal. Chill for at least 45 minutes or freeze (for up to 3 months) until needed.
Before baking, preheat oven to 375° F. Unwrap the dough (if frozen, let thaw for 5 minutes). On a cutting board, cut it into slices about 1/4 inch thick. Place the slices about 1 inch apart on an ungreased baking sheet. Bake for 10 to 12 minutes. Let cool until the cookies are firm enough to be moved. Transfer to a rack to cool completely.