1½ cups sifted all-purpose flour
1½ teaspoons baking powder
¼ teaspoon salt
¾ teaspoon cinnamon
¼ teaspoon allspice
½ teaspoon finely, freshly ground black pepper
Pinch of cayenne pepper
¾ cup unsweetened cocoa powder (preferably Valrhona)
6 ounces (1½ sticks) unsalted butter
1½ teaspoons vanilla extract
1 cup granulated sugar
Sift together the flour, baking powder, salt, cinnamon, allspice, black pepper, cayenne and cocoa, and set aside. In the large bowl of an electric mixer, cream the butter. Add the vanilla and sugar and beat well. Beat in the egg to the mix. On low speed, gradually add the sifted dry ingredients, scraping the bowl with a rubber spatula, and beating only until thoroughly mixed.
Tear off a strip of wax paper about 16 inches long. Place the dough by heaping tablespoonfuls down the length of the paper, forming a heavy strip about 10 inches long. Fold the long sides of the paper up around the dough. Pressing against the paper with your hands, shape the dough into an even oblong about 12 inches long and 2¾ inches thick. Wrap the dough in the paper. Slide a cookie sheet under the paper and transfer the dough to the freezer or refrigerator for several hours until firm.
Adjust two racks to divide the oven into thirds, and preheat oven to 375ºF. Line cookie sheets with parchment.
Unwrap the firm dough. Place it on a cutting board, and with a sharp knife, cut the dough into ¼-inch slices. Place the slices 1 inch apart on the cookie sheets.
Bake for 10-12 minutes, reversing the sheets top to bottom and front to back to ensure even baking. The cookies are done when the tops spring back when pressed with a fingertip. Do not overbake.
Transfer cookies to wire racks to cool.