Add the flour, baking powder, caster sugar and salt to a bowl and mix
Add the lemon zest, eggs, oil and mix
Add to a bowl and chill for an hour
Preheat the oven to 190ºc/170ºfan and line two large baking trays
Grab tablespoon scoops of the cookie dough and roll into a ball
Roll these into icing sugar and place onto the trays
Bake in the oven for 10 minutes
Leave to cool and enjoy
Notes
If you want these to be slightly more yellow in colour, you can add some food colouring to the cookie dough but I personally don't bother.
You can swap the lemon zest to 2tsps of lemon extract, but avoid using lemon juice as it's too much 'wet' for the dough and won't bring the flavour you want.
These will last for 4-5+ days at room temperature, and they will also freeze for 3+ months