- 1 cup all-purpose flour
- 2/3 cup packed dark brown sugar
- 2 tablespoons unsweetened cocoa powder
- 1/2 teaspoon salt
- 7 oz fine-quality bittersweet chocolate (not unsweetened), finely chopped
- 1/2 stick (1/4 cup) unsalted butter, cut into pieces
- 2 large eggs
- 2 teaspoons finely grated fresh orange zest
- 1/2 cup chilled heavy cream
- 1 teaspoon sugar
- 4 navel orange segments, membranes discarded from each and fruit cut into 1/4-inch pieces
- Special equipment: 2 (12-inch-long) sheets of parchment paper; a 1 1/2-inch round fluted cookie cutter
- Whisk together flour, brown sugar, cocoa powder, and salt in a bowl.
- Melt chocolate and butter in a metal bowl set over a saucepan of barely simmering water, stirring occasionally, until smooth. Remove bowl from heat and stir in eggs, zest, and flour mixture until just combined. (Dough will be soft.)
- Roll out dough between parchment sheets into an 8-inch round (1/2 inch thick). Transfer round (still in parchment) to a large baking sheet and chill until firm, at least 1 hour, or freeze at least 30 minutes.
- Preheat oven to 350°F.
- Remove top sheet of parchment paper and replace it loosely. Flip over paper-enclosed round and discard paper now on top. Cut out about 20 cookies with cookie cutter and arrange about 1 inch apart on a buttered large baking sheet. Reroll scraps between parchment sheets and cut out 12 more cookies (chill or freeze dough as needed if it becomes too soft to handle).
- Bake cookies in middle of oven until matte (dough will start out shiny and turn dull), about 10 minutes, then transfer with a spatula to a rack to cool completely. (Cookies will have a fudgy consistency.)
- Beat cream and sugar with an electric mixer until it just holds stiff peaks. Top each cookie with 1/2 teaspoon cream and a piece of orange.