Cream the butter and sugar.

In a large mixing bowl, use a hand mixer or stand mixer to beat ½ cup of butter with 1 cup of granulated sugar on medium-high speed. Continue mixing for about 2 minutes, until the mixture becomes pale and fluffy.

Incorporate the wet ingredients.

Add the egg, extra yolk, 2 tablespoons of lemon juice, 1 1/2 tablespoons of lemon zest, 1 teaspoon of vanilla extract, and ½ teaspoon of lemon extract. Mix on high speed for about 1 minute, or until everything is fully blended.

Combine the dry ingredients.

In a separate bowl, whisk together 2 cups of flour, ¼ teaspoon salt, and ½ teaspoon baking soda. Gradually add this dry mixture to the wet ingredients, stirring just until combined.

Chill the dough.

Cover the dough securely and refrigerate for at least 1 hour.

Prepare for baking.

Preheat the oven to 325°F and line baking sheets with parchment paper. Place granulated sugar in one bowl and powdered sugar in another.

Shape and coat the dough.

Scoop out portions of dough and roll them into 1-inch balls. Roll each ball in granulated sugar first, then generously coat with powdered sugar. Arrange them on the baking sheets about 2 inches apart.

Bake.

Bake for 12–13 minutes, until the edges are firm but the centers still appear slightly soft. Allow the cookies to rest on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.