Baci di Dama (Italian Chocolate-filled Hazelnut Cookies)

Ingredients:

• 3/4 cup hazelnuts. toasted, any loose skins removed, and cooled
• 1 cup confectioners sugar
• 1 stick (1/2 cup) unsalted butter, softened
• 1/4 tsp grated lemon zest
• pinch of salt
• 1 cup all-purpose flour
• 3 oz 70% dark chocolate, chopped

Directions:

• Put oven rack in middle position and preheat to 350 degree. Line 2 or 3 baking sheets with parchment paper.
• Grind nuts with confectioners sugar in food processor until powdery.
• Beat together butter, zest, salt and nut mixture in a large bowl with a rubber spatula until creamy, then add flour, stirring until just incorporated.
• Roll lever 1/2 teaspoon of dough into tiny balls and arrange 1 inch apart on baking sheets. Bake until pale golden, 12 to 14 minutes, then slide parchment with cookies onto a rack to cool completely.
• Melt chocolate in a double boiler pan, stirring occasionally, until smooth. Spoon melted chocolate into a small plastic bag and seal, forcing out excess air. Snip off 1 bottom corner of bag with scissors to form a small hole.
• Pipe a small mound of melted chocolate onto flat sides of cookies and top with other cookies, pressing flat sides together to help adhere. Repeat with remaining cookies.