Preheat oven to 175°Celsius.
Prepare and line a baking tray with parchment paper.
In a small bowl, measure and sift the icing sugar.
Measure and cut butter into small pieces. Add to the powdered sugar.
Cream both the butter and sugar until creamy and well combined.
Sift in the flour and mix until the flour is well combined. Scrape the sides of the bowl and bring the dough together. It will be very soft and sticky at this stage.
Let the dough rest for 10 to 20 minutes.
Scoop the dough into 1 tablespoon size. Form the dough into round balls and place them on the prepared baking tray. Give each ball sufficient space to be flattened and spread lightly during baking.
Using a fork dipped in flour, flatten each cookie ball lightly, imprinting the fork lines horizontally on them. Lif the fork, dip in flour again, and press on the cookies again, this time vertically. Repeat for all the cookie balls.
Bake the cookies for 8 to 10 minutes, until the sides begin to turn light golden.
Remove cookies from the oven. Let them rest in the tray for 5 minutes before transferring them onto a wire rack to cool completely.
Store the cookies in an airtight container.