Preheat your oven to 190 degrees C.
In a large mixing bowl, add sugar, softened butter, eggs, vanilla, baking powder, salt, and cocoa powder. Mix until combined.
Add the flour one cup at a time, while mixing and allowing it to be combined each time.
The dough will be fluffy and soft. Wrap it in clear plastic wrap and shape it into a ball with the wrap's help. Put the dough wrapped up into the freezer for half an hour or until the dough can be worked with.
Take the dough out. To roll it out, line your surface with plastic wrap and cocoa powder. Another way would be to roll the dough out directly onto baking paper-lined sheets. Roll it out to be about 1/2 cm thick. Use cookie cutters to cut out your cookies.
Put the cookies onto the baking paper-lined sheet and put it into the oven. Bake for about 8 minutes, depending on the thickness of your cookies. They will be soft to the touch when taking them out, but don't overbake them.
Get them out of the oven and let them cool down on the baking sheet for 5 minutes. Place them onto a cooling rack until they are completely cooled down. You can store them in an air-tied container and decorate them with icing.