Add the butter and sugar to a large mixing bowl and beat with a handheld electric whisk until light and fluffy.
1/2 cup unsalted butter, 1 cup granulated sugar
Add the vanilla extract, egg, lemon zest and juice and beat again until creamy.
1 teaspoon vanilla extract, 1 large egg, zest of two large lemons, juice of two large lemons
Sift the flour, baking soda, and salt into the bowl.
2 1/4 cups all purpose flour, 1 teaspoon baking soda, 1/4 teaspoon salt
Beat on the lowest speed until combined. Take care not to over-mix.
Cover the bowl with plastic wrap and put in the refrigerator for at least 4 hours.
When you are ready to begin baking, put the granulated sugar and powdered sugar into separate small bowls.
1/4 cup granulated sugar, 3/4 cup powdered sugar
Preheat the oven to 350°F and line two cookie sheets with parchment paper.
Remove the cookie dough from the refrigerator and use a tablespoon to scoop out portions. Roll each portion into a ball with your hands then dip the ball into the granulated sugar to coat. Next, coat it very well with the powdered sugar rolling multiple times so that the cookie ball is completely coated.
Place the cookie balls on the parchment paper with 8 on each cookie sheet leaving some space in between. You can work in batches, returning the dough to the refrigerator between batches.
Bake in the middle of the preheated oven for 12 minutes or until the cookies have spread into a cookie shape and have cracked on the top.
Remove from the oven and leave to cool on the baking sheet for 2 minutes then place on a wire rack until cool enough to eat.
Enjoy warm or at room temperature.