1-Making the Cookie Dough: Start by infusing the sugar with lemon flavor. In a food processor, pulse the granulated sugar and fresh lemon zest until the sugar is moistened and the zest is finely chopped. This technique releases the lemon oils and distributes flavor evenly throughout the dough. According to lemon zest experts, this method maximizes flavor extraction for superior results.

2-Making the Cookie Dough: In a large bowl, beat the lemon sugar mixture with the cold unsalted butter on high speed until creamy, about 3 minutes, scraping the sides as needed. The cold butter is crucial here, as it helps maintain the proper dough structure for classic shortbread texture.

3-Making the Cookie Dough: Add the fresh lemon juice and pure vanilla extract to the butter mixture, and beat until combined. Next, add the all-purpose flour, cornstarch, and salt, then beat on low speed for 1 minute, followed by medium speed until the dough clumps together, about 1 to 3 minutes. The dough will be thick and soft, which is exactly what you want.

4-Chilling and Shaping the Dough: This step cannot be rushed for perfect lemon shortbread cookies. Dust a parchment paper or silicone mat with flour, roll out the dough to about 1/4 to 1/2 inch thick using a floured rolling pin, and transfer it on the parchment or mat to a baking sheet. Cover and refrigerate for at least 3 hours or up to 2 days.

5-Chilling and Shaping the Dough: After the dough has chilled, preheat your oven to 350°F (177°C) and line baking sheets with parchment or silicone mats. Cut the chilled dough into shapes with cookie cutters, re-rolling scraps as needed. If you notice the dough becoming soft as you work, refrigerate the shaped cookies for 15 minutes before baking.

6-Chilling and Shaping the Dough: Optionally, add decorative indents with a fork and sprinkle with coarse sparkling sugar if you’re not planning to use icing. This adds both visual appeal and a delightful texture contrast.

7-Baking to Perfection: Bake the cookies for 14 to 15 minutes, or until the edges are set and beginning to turn golden. Adjust the time slightly if you’ve made smaller or larger cookies. The centers might look slightly underdone, which is perfect as they will continue to set as they cool.

8-Baking to Perfection: Cool the cookies on the baking sheet for 10 minutes, then transfer to a wire rack to cool completely. This cooling process is essential for the cookies to develop their signature shortbread texture.

9-Preparing and Applying the Lemon Icing: While the cookies cool, prepare the icing by whisking together the confectioners’ sugar, fresh lemon juice, milk or heavy cream or half-and-half, and pure vanilla extract until smooth. The consistency should be fluid enough to dip but thick enough to cling to the cookies.

10-Preparing and Applying the Lemon Icing: Dip the cooled cookies in the icing, let excess drip off, and place them on a rack or baking sheet to dry. Add fresh lemon zest as a garnish on the wet icing if desired. Let the icing set for 1 to 2 hours. This waiting period ensures the icing firms up properly, making the cookies easier to stack and transport.