In a bowl sift together all purpose flour, unsweetened cocoa powder and salt. Set aside.
In the steel bowl of your stand mixer fitted with paddle attachment or using your hand mixer beat together butter and sugar till smooth and creamy, around 2 minutes.
Add in the egg, vanilla extract and mix till combined.
Now add the flour mix in 3 parts, mixing well after each addition.
You will know the dough is done when it starts sticking to the paddle attachment.
Remove dough and place it in a cling sheet.
Wrap and refrigerate for 2 hours or overnight.
Once chilled, roll the dough to 1/4 inch thickness.
Cut out cookies using your cookie cutters of your choice. Repeat till entire dough is finished.
Arrange all the cookies in a baking sheet lined with parchment paper, leaving 1-2 inch space between them.
Place the baking tray in the refrigerator for 1 hour.
Preheat oven to 350 F degrees.
Take out the tray from the refrigerator and bake at 350 F degrees for 9-11 minutes. The time will vary depending on the size of the cookies. My cookies were huge so I baked them for 11-12 minutes.
Take out of the oven and let them cool down in the baking tray. They are very soft and will break if you try to transfer them on to a wire rack after 5 minutes or so.
Once they have cooled down considerably, transfer on to a wire rack to cool completely.