1tablespoonfreshly squeezed lemon juice, from about 1/2 lemon
1 ½cups(213g)all-purpose flour
Preheat oven to 350 degrees. Line rimmed baking sheets with silpat liners, parchment or lightly coat with cooking spray.
In a large bowl, cream butter and sugar together until light and fluffy. Add vanilla, egg, lemon zest and juice and mix well, scraping down the sides as needed. Add the dry ingredients (except the powdered sugar) and mix until just combined. Place the powdered sugar on a large plate or shallow pie dish. Roll tablespoon-size balls of dough in the powdered sugar to coat. Place on the prepared baking sheets, about 2 inches apart.
Bake the cookies for 9-11 minutes. The cookies will not be browned on the edges but they will have lost a bit of their shininess on top. Don't overbake! Cool the cookies on a cooling rack and store in an airtight container or eat immediately.
Lemon: the recipe calls for a teaspoon of lemon zest. I didn't really measure, I just grated the zest from the lemon I was using and threw it in there. My guess is it was more like 2 teaspoons.