Mix dry ingredients in a bowl (flour, baking powder and salt).
In another bowl, rub the sugar and lemon zest with your hand until you reach a yellow pastel color (it helps infusing the lemon flavor)
Add eggs and whisk until combined, then add butter, lemon juice and vanilla.
Add dry mix gradually and mix using a spatula.
Cover the mixture and put in the fridge until the next day.
Preheat oven to 180c
Scoop out cookie balls, roll them in the caster sugar bowl, then the powder sugar.
Place in trays with baking paper. Bake for 15 minutes.
Allow to cool before trying.
