- 1 cup blanched hazelnuts, toasted
- 1 cup (2 sticks) unsalted butter, room temperature
- 1/2 cup granulated sugar
- 1 large egg, room temperature
- 1 teaspoon pure vanilla extract
- 2 cups plus 2 tablespoons unbleached all-purpose flour, plus more for dusting
- 1 teaspoon baking powder
- 1 teaspoon ground cinnamon
- 1/2 teaspoon kosher salt
- 1/4 teaspoon freshly ground nutmeg
- Confectioners’ sugar, for dusting
- 1/2 cup jam
- Pulse hazelnuts in a food processor until finely ground.
- In the bowl of an electric mixer fitted with the paddle attachment, beat together butter and granulated sugar on medium speed until light and fluffy, about 2 minutes. Add egg and beat until smooth. Beat in vanilla.
- Whisk together ground hazelnuts, flour, baking powder, cinnamon, salt, and nutmeg. Add to butter mixture; beat on low speed until just combined. Divide dough in half; shape each half into a flat disk and wrap in plastic. Refrigerate until firm, at least 1 hour or up to overnight.
- Preheat oven to 350 degrees. Line two baking sheets with parchment. On a lightly floured surface, roll out one disk of dough 1/4 inch thick. Using a 3 1/2-inch flower-shaped cutter, cut out cookies. (If dough becomes too soft, freeze 10 minutes.) Using a large spatula, transfer to prepared baking sheets. Using a 3/4-inch petal-shaped cutter, cut out centers of petals from half the cookies. Repeat process with remaining disk of dough. Gather scraps from both disks, reroll, and cut.
- Bake, rotating halfway through, until edges are slightly golden, 12 to 14 minutes. Transfer sheets to wire racks and let cool completely.
- Lightly sift confectioners’ sugar over cookies with cutout petals. Spread a heaping teaspoon of jam on each solid cookie; carefully sandwich with sugared cookies.