Mix flour, cocoa powder, sugar, and salt together.
Dissolve yeast in warm milk and add it to the mixture.
Add room-temperature butter and knead the dough, then let it rise for 1 hour.
Shape the dough into round pieces and let rise a second time.
Bake in a preheated oven at 180°C for 15 minutes.
Make the chocolate sauce and drizzle it over the baked bread.