- 2 cups all-purpose flour, plus more for surface
- 1 cup plus 1 tablespoon sugar
- 1/2 cup unsweetened Dutch-process cocoa powder
- 3 tablespoons ground chicory, preferably Cafe du Monde, or 1 tablespoon instant-espresso powder (optional)
- 1 teaspoon baking powder
- 1 1/2 sticks cold unsalted butter, cut into 1/2-inch pieces
- 2 large eggs plus 2 large egg yolks
- 1 cup semisweet chocolate chips (6 ounces)
- 1 tablespoon heavy cream
- Combine flour, 1 cup sugar, cocoa, chicory, and baking powder in the bowl of a mixer. Add butter and beat on medium speed until sandy, about 3 minutes. Reduce speed to low, and gradually beat in eggs and 1 egg yolk. Add chocolate chips and mix until just combined.
- Divide dough in half and roll each half into a 1 1/2-inch-thick log (about 12 inches long) on a lightly floured surface. Wrap each log in plastic wrap. Refrigerate for at least 1 hour.
- Preheat oven to 325 degrees. Unwrap logs; transfer to a parchment-lined baking sheet. Whisk together remaining egg yolk and cream. Brush tops of logs with egg wash and sprinkle with remaining tablespoon sugar. Bake until firm, about 35 minutes.
- Transfer logs to a wire rack and let cool completely. Cut each into 1 1/4-inch-wide wedges with a serrated knife by alternating the angle of the knife as you slice crosswise.
Unbaked dough logs can be refrigerated for up to 1 week or frozen for up to 1 month. Thaw before baking. Cookies can be stored at room temperature for up to 1 week.