In a large bowl, mix together the flour, salt, and baking soda. Set aside.

In the bowl of a stand mixer, beat the butter and sugar until fluffy. Add the egg, lemon juice, lemon zest, vanilla extract, and food coloring (if using) and mix to combine.

Slowly add the dry ingredients to the stand mixer and mix until they are incorporated. Cover the bowl with plastic wrap and place in the fridge to set for 2 hours.

Preheat the oven to 350F and line 2 baking sheets with parchment paper.

Scoop out the dough and roll it into a ball. Roll the dough balls in regular sugar first and then in powdered sugar. Place the dough balls on the baking sheets, 2 inches apart.

Bake the cookies for 10-12 minutes. Remove them from the oven and allow the cookies to cool on a baking sheet for 5 minutes before transferring to a cooling rack to cool completely.