Pre heat oven to 160c and line 2 baking sheets with baking paper.
In a stand mixer or bowl for a hand mixer, place in your butter and icing sugar.
Beat the butter and sugar until light and creamy.
Add in your cocoa powder, salt and flour and beat until everything is well combined and a dough forms.
Remove the dough onto a piece of baking paper or floured surface and roll to 1/2cm (less than 1/4 inch) thick.
Use a 5cm round cutter (or cutter of your choice) and cut the cookies.
Place onto baking sheets and place in the oven for 15 - 17 minutes.
Remove from the oven and set aside to cool.