Take a bowl. Add maida & baking powder.
Add butter, vanilla essence, powdered sugar & an egg.
Bind them well to form a soft dough.
Keep the dough in fridge for 20 minutes.
Preheat the oven at 180 degree for 10 minutes.
Now take the dough, spread it with a help of a rolling pin.
Take a cookie cutter and cut the dough.

Keep each on a baking tray & sprinkle castor sugar on that.
Bake it for 18 minutes. But make sure that you have to take the tray out in half time (After 9 minutes) change the side of the tray & keep it for another 9 minutes.
PS: You have to change the side of the tray, no need to flip the cookies.