Ingredients
1 cup all-purpose flour, plus more for work surface
1/4 cup plus 1 tablespoon sugar
1/4 cup unsweetened cocoa powder
1/2 teaspoon salt
1/2 teaspoon ground cinnamon
1/4 teaspoon ground cloves
1/2 cup (1 stick) cold unsalted butter, cut into small pieces
1 large egg
4 ounces best-quality semisweet chocolate, finely chopped
Preparation
In the bowl of an electric mixer fitted with the paddle attachment, combine flour, sugar, cocoa, salt, cinnamon, and cloves. Add butter; mix on low speed until butter is the size of small peas, about 5 minutes. Add egg; mix until ingredients come together to form a dough.
Preheat oven to 350 degrees. On a lightly floured work surface, roll out dough to just thicker than 1/8 inch. Brush off excess flour; transfer dough to a 10-inch tart pan with a removable bottom. Press dough into bottom and up sides of pan; trim excess flush with edge. Lightly prick bottom of dough all over with a fork. Chill until firm, about 30 minutes.
Bake shell until firm, about 15 minutes. Immediately sprinkle chocolate over bottom of shell; smooth with a spatula.
