Preheat oven to 350 degrees. Line 2 cookie sheets with parchment paper.
Whisk together the flour, baking powder, baking soda and salt in small bowl. Set aside.
In a larger bowl, cream the butter and 1 cup sugar until the mixture is combined and light in texture.
Pour in wet ingredients starting with the fresh squeezed lemon juice then the vanilla.
Add in the egg and the lemon zest from 2 lemons and mix until just combined.
Slowly stir in the flour mixture a little at a time, gently mixing as you go until well combined.
In a small bowl, mix together the 1/2 cup sugar and the zest from the 3rd lemon.
Chill the dough in the fridge for at one hour.
Once dough is chilled use a cookie scoop to form the dough into tablespoon sized balls and then roll in the sugar/lemon mixture before placing on the cookie sheet 2 inches apart.
Bake for 10-11 minutes, until the tops are no longer wet looking and cracks start to form.
Allow the cookies to cool for an additional 5 minutes on the cookie sheet and then transfer to a cooling rack or wax paper.