Ingredients

2 sticks (8 ounces; 230 grams) unsalted butter, at room temperature

2/3 cup (70 grams) confectioners’ sugar, sifted

2 large egg yolks, at room temperature

Pinch of salt

2 teaspoons pure vanilla extract

Grated zest of 1 to 1 1/2 lemons (to taste)

2 cups (280 grams) all-purpose flour

Approximately 1/2 cup (100 grams) sugar, for coating

Preparation

  1. Put the butter in the bowl of a mixer fitted with the paddle attachment and beat at medium speed until it is smooth. Add the sifted confectioners’ sugar and beat again until the mixture is smooth. Beat in 1 of the egg yolks, followed by the salt, vanilla, and grated lemon zest. Reduce mixer speed to low and add the flour, beating just until it disappears. Do not overbeat; if the flour isn’t fully incorporated, just blend in remaining flour with a rubber spatula. Turn the dough out onto a counter, gather it into a ball, and divide it in half. Wrap each piece of dough in plastic wrap and refrigerate for about 30 minutes.

  2. On a smooth surface, form each piece of dough into a log that is about 1 to 1 1/4 inches thick. Wrap the logs in plastic and chill for 2 hours. (The dough can be kept refrigerated for up to 3 days or in the freezer for up to 1 month.)

  3. Position the racks to divide the oven into thirds and preheat the oven to 350°F. Line two baking sheets with parchment paper.

  4. While the oven is preheating: Whisk the remaining egg yolk in a small bowl until it is smooth and liquid. Spread the sugar out on a piece of wax paper. Remove the logs of dough from the refrigerator, unwrap them, and brush lightly with egg yolk. Roll the logs in the sugar, pressing the sugar gently if necessary, then, using a sharp slender knife, slice each log into cookies about 1/4 inch thick. Place the cookies on the lined baking sheets, leaving about 1/2 inch space between them.

  5. Bake the cookies for 12 to 14 minutes, or until they are set but not browned. (It’s fine if the yolk-brushed edges brown a bit.) Cool on racks to room temp.

Keeping: Packed airtight, the cookies will keep for about 5 days at room temperature. These cookies are not suitable for freezing.