Preheat your oven to 190c or 170c for fan ovens
Cream sugar and butter in a mixer or a mixing bowl. The secret to knowing when butter and caster sugar is creamed is to look out for the change of colour (It will go lighter).
Add cocoa powder and flour and mix until you have a smooth paste.
Wrap the dough in cling film and pop in the fridge for 20 minutes.
Take out and roll out on a floured to 1cm thick and cut out your shapes.
Prick with a fork or stamp.
Cook for 18 minutes.
Remove and allow to cool on a wire rack.