Cream the butter and sugar together til smooth.
Beat in the egg til combined.
Sift over the flour and cocoa powder.
Combine to make a dough.
Leave the dough to chill for at least an hour.
Divide the dough into three batches. Return two to the fridge.
Roll out the dough to 10mm thick
Press the cookie cutter into the dough to cut out the square tiles
Then flip the cookie cutter over and then emboss each tile.
Repeat with the other balls of dough and then place all the tiles onto a few baking trays lined with greaseproof paper.
Put the oven on to preheat to 200C/180C Fan
While it is preheating, you can rest the cut out and embossed tiles in the fridge.
Bake for about 10 minutes
Leave to cool completely before playing.