Sift the flour and cocoa powder.
Add sugar, yeast, salt, milk, egg, and butter and knead the dough.
Mix in the dark chocolate.
Let the dough rise for the first fermentation for 1 hour.
Shape the dough and place it on a pan.
Let the dough rise for the second fermentation for 30 minutes.
Bake at 180°C for 20 minutes.
Cool before serving.