Cream the butter and the powdered sugar together, add the egg yolk, mix, then add the teaspoon of water and vanilla extract then mix again.
Add the cake flour and mix well then knead the dough until it all comes together and smooth.
Form into a ball and wrap it with cling film and refrigerate for about an hour or even overnight.
Roll out the dough between two parchment paper for smoother and easier rolling until desired thickness.
Cut using cookie cutter, place on a tray with parchment paper then bake in a pre-heated 170°C oven for about 10 minutes or until cooked.