Beat butter and sugar until fluffy

Sift over the butter and sugar the cocoa and the flour

Add the salt and vanilla extract

Crack eggs in another bowl (to make sure they are ok) and add to the mixture

Beat together until they form a dough (it will not be soft)

Add the chocolate chips and mix

Chill for about 1 hour in the fridge

Take out of the fridge and make little balls in your hands out of the dough then flatten them a bit and put them on a wax sheet over an oven tray

Bake on medium heat about 8 to 10 minutes