1 1/2 cups pecan halves, plus about 32 pecan halves for pressing onto unbaked cookies
1/3 cup confectioners' sugar (1.25 ounces)
1/2 cup packed light brown sugar (3 1/2 ounces)
1 1/2 cups unbleached all-purpose flour (7 1/2 ounces)
1/2 teaspoon kosher salt
12 tablespoons unsalted butter, 1½ sticks (chilled), cut into 1/2-inch cubes
1 large egg yolk
1. Preheat the oven to 350 degrees F. Spread the 1½ cups of pecans out in one layer on a baking sheet and bake them, stirring occasionally, until fragrant and lightly toasted, 5-7 minutes. Transfer the pan to a wire rack to cool.
2. Process the cooled toasted 11/2 cups of pecans with both sugars in food processor until nuts are ground, about twenty 1-second pulses. Add flour and salt and process to combine, about twelve 1-second pulses. Scatter butter pieces over dry ingredients and process until mixture looks like damp sand and rides up sides of bowl, about eighteen 1-second pulses. With machine running, add yolk and process until dough comes together into rough ball, about 20 seconds.
3. Turn dough (it will look scrappy and uneven) onto clean, dry work surface and gently knead until it is evenly moistened and cohesive. Using palms of your hands, roll dough into even 12-inch log; cut log in half and wrap each half in plastic wrap. Freeze dough logs until very cold but still malleable, about 30 minutes. Remove from freezer, unwrap, and roll on work surface to round off flat sides. Rewrap logs in plastic wrap and refrigerate until thoroughly chilled and completely firm, about 2 hours.
3. Adjust oven racks to upper-middle and lower-middle positions and heat oven to 325 degrees. Line 2 large baking sheets with parchment paper or spray with nonstick cooking spray. Unwrap dough logs and, using sharp chef's knife, slice logs into coins 1/4 inch thick, slightly rotating logs after each slice so that they do not develop markedly flat sides. Place slices on prepared baking sheets, spacing them about 3/4 inch apart. Press pecan half in center of each slice.
4. Bake until edges of cookies are golden brown, about 24 minutes, rotating baking sheets front to back and top to bottom halfway through baking time. Cool cookies 3 minutes, then transfer to rack and cool completely.
-Recipe courtesy of James Moore