Bring the water, sugar, salt, dark chocolate and butter slowly to a boil.
Add the sifted flour and cacao powder and dry the mass over a hot fire.
Bring over in a stirring mixer and let the choux mass turn for 2 minutes to let escape the most heat.
Add the eggs systematically until the mass is smooth.
Spread between 2 plastic sheets ( +/- 1cm) and freeze.
Cut out circles of 6 cm diameter and set apart.