Yield: approximately 2 dozen cookies
½ cup unsalted butter, softened
1/3 cup plus 2 tablespoons sugar, divided
2 large egg yolks
1 teaspoon vanilla extract
1¼ cups all-purpose flour
¼ cup natural unsweetened
1/8 teaspoon salt
½ cup chocolate-hazelnut spread, such as Nutella
1. In a medium bowl, beat butter and 1⁄3 cup sugar at medium-high speed with an electric mixer until creamy, about 4 minutes. Add egg yolks and vanilla, beating until combined.
2. In another medium bowl, sift together flour, cocoa, and salt. With mixer on lowest speed, add flour mixture to egg mixture in three batches, beating well after each addition.
3. Place dough between two pieces of parchment paper; roll to 1⁄4-inch thickness. Refrigerate for 1 hour.
4. Preheat oven to 350°. Line 2 baking sheets with parchment paper. Set aside.
5. Remove dough from refrigerator, removing top sheet of parchment paper. Using a 11⁄2-inch round fluted cutter, cut as many cookies as possible, rerolling scraps as necessary. Place cookies 1 inch apart on prepared baking sheets. Sprinkle cookies with remaining 2 tablespoons sugar.
6. Bake until firm, 10 to 12 minutes. Let cool on pans for 10 minutes. Remove from pans, and let cool completely on a wire rack.
7. Once cookies are cool, spread approximately 1 teaspoon chocolate-hazelnut spread on flat sides of half of cookies; top with remaining cookies, flat sides down. Store in an airtight container at room temperature for up to 3 days.