Mix soften butter and sugar then add in flour and cocoa powder

Pour in on a flim then roll up like a log of candy..

Chill it for minimum 1 hour or longer then slice into 1 cm thick, **optional at this stage you can chill it up to 3 days or freeze 1 month**

Baked on parchment paper at 180 C for 12 to 15 minute then cool it on rack, the cookies will look soft but it will harden up once it is totally cooled