Toasted Almond Butter Cookies

To make the cookies: Place flour, confectioners’ sugar, salt, and lemon zest in the bowl of a food processor fitted with the metal blade. Pulse three times to mix. Add butter and pulse until crumbly. Add egg yolks and pulse until mixture comes together.

Remove dough from bowl of processor, divide in half, and shape each half into a disk. Wrap in plastic wrap or wax paper and chill for at least 2 hours, or until firm enough to form into balls.

Set the oven rack in the middle position. Preheat the oven to 350°F. Line a 14-inch by 16-inch baking sheet with foil, shiny side up, and coat with vegetable spray, or use a silicone liner.

Roll heaping teaspoons of dough into balls the size of marbles. Place 12 to 15 balls on each baking sheet.

To add the topping: In a small bowl, whisk egg whites to break them up. Cut out a 4-inch by 4-inch square of wax paper. Place the wax paper on top of a ball. Using the bottom of a drinking glass, gently press the ball flat. Continue to do this with each ball. (This method eliminates using any excess flour, but if you prefer, you can flatten cookies with the bottom of a glass dipped in flour.) Brush tops of cookies with egg white and sprinkle with slivered almonds. With your fingers, gently press the almonds into the dough. Bake 10 to 12 minutes, or until edges of cookies turn golden brown. Place baking sheet on rack and cool for 3 minutes. Remove cookies from baking sheet with a metal spatula and place on rack to cool completely. Store between sheets of waxed paper in a covered tin.