Preheat oven to 350 degrees. Prepare a cookie sheet with a non-stick spray, or parchment paper, set aside In a medium bowl whisk the flour, baking soda, salt, and lemon zest. In large mixing bowl beat the butter for a few seconds, add the sugar and mix until light and fluffy. Add in the egg, vanilla, and lemon juice. Mix until fully combined. Continue mixing while you add in the dry ingredients. Mix until fully combined. Drop dough by the spoonful onto cookie sheet. Bake until light golden on edges, 12-14 minutes. Cool on the cookie sheet about 5 minutes then move to wire rack. Once cooled prepare the glaze by whisking the powdered sugar, lemon juice, and lemon zest together until well combined. Spoon onto the top of the cookies. Allow to sit and dry, glaze will harden. Store cookies in airtight container at room temperature.