Sift and mix flour and cocoa powder together.
Add sugar, salt, and yeast, then mix well.
Add milk, eggs, and melted butter and knead the dough.
Let the dough rise in a warm place for 1 hour (first fermentation).
Divide the dough and shape it into rounds.
Add chocolate chips and reshape into balls.
Line a pan with parchment paper and place the dough on top.
Let rise for another 30 minutes (second fermentation).
Bake in a preheated oven at 180°C for 20 minutes.