- 1 1/2 cups hazelnuts (9 ounces), toasted , loose skins rubbed off in a kitchen towel while still warm, and nuts cooled completely
- 3/4 cup sugar
- 1/2 cup all-purpose flour
- 1/2 cup unsweetened cocoa powder (not Dutch-process)
- 1 teaspoon baking soda
- 3/4 teaspoon salt
- 1/2 teaspoon ground cinnamon
- 1/8 teaspoon ground cloves
- 3 tablespoons cold unsalted butter, cut into 1/2-inch cubes
- 1 tablespoon grated orange zest
- 3 tablespoons fresh orange juice
- 1 tablespoon hazelnut-flavored liqueur (preferably Frangelico)
- 1/2 cup confectioners sugar
- 1/2 cup unsweetened cocoa powder (not Dutch-process)
- 3 tablespoons water
- 1 tablespoon hazelnut-flavored liqueur
- Preheat oven to 325°F with rack in middle. Butter a large baking sheet.
- Pulse hazelnuts, sugar, flour, cocoa powder, baking soda, salt, cinnamon, and cloves in a food processor until nuts are finely chopped, then add butter and zest and pulse until mixture resembles coarse meal with some small (roughly pea-size) butter lumps. Add juice and liqueur and pulse until dough comes together into a ball but is still crumbly. Form level tablespoons of dough into balls and flatten to about 1 1/2 inches in diameter, arranging 1 inch apart on baking sheet.
- Bake cookies until puffed and slightly cracked, about 15 minutes. Transfer to a rack to cool completely.
- Whisk together all icing ingredients until smooth.
- Dip tops of cooled cookies into icing and transfer to a wax-paper-lined baking sheet. Let stand until icing is set, about 1 hour.