Prep and Cook Time: about 1 1/4 hours. Notes: To toast the hazelnuts, place whole nuts in an 8- or 9-inch-wide pan and bake in a 350° oven, shaking pan occasionally, until golden brown under skins, 10 to 12 minutes. Pour nuts onto a clean kitchen towel and rub to remove loose skins; lift nuts from towel, leaving skins behind. When nuts are cool, whirl in a food processor or blender to grind. Store these cookies airtight for up to 1 week.
1 cup (1/2 lb.) butter, at room temperature
1 2/3 cups powdered sugar
2 teaspoons vanilla
1 2/3 cups all-purpose flour
2 1/2 teaspoons ground cinnamon
1/2 teaspoon baking powder
3/4 cup ground toasted hazelnuts (see notes)
How to Make It
In a bowl, with an electric mixer on medium speed, or in a food processor, beat or whirl butter, 1/3 cup powdered sugar, the vanilla, the flour, 1/2 teaspoon cinnamon, and the baking powder until smooth and well blended. Stir in hazelnuts.
Shape dough into 3/4-inch balls and, using your fingers, roll each into a 1 1/2-inch rope tapered to points at ends. On buttered or cooking parchment-lined 12- by 15-inch baking sheets, form each rope into a crescent.
Bake cookies in a 300° oven until pale golden, 20 to 25 minutes; if baking more than one pan at a time, switch pan positions halfway through baking. Let cool on sheets for 5 minutes.
In a shallow bowl, mix remaining 1 1/3 cups powdered sugar with remaining 2 teaspoons cinnamon. Gently turn warm cookies in powdered sugar mixture, a few at a time, then set on racks to cool. When cool, coat cookies again with powdered sugar mixture.