Preheat oven to 350F and line a cookie sheet with parchment.
In a small bowl and a fork/whisk cream together butter and sugar until light and fluffy (took me a few min). Add lemon and lemon zest.
In a mug/other bowl mix flour, baking powder, pinch of salt.
Gradually add dry to wet, stopping as soon as you get a nice soft cookie dough (I had about 1/2 tbsp dry mixture left). If the dough gets too crumbly add a drop of water.
Roll cookie dough between your palms (roll in sugar if you like) and place on the parchment.
Bake 10 minutes, cool for 5 and enjoy!
Notes
If you don't have a food scale, remember to use the spoon & level method in measuring flour to avoid over-measuring, which will lead to dry cookies.