In a bowl, mix the flour, bitter cocoa, brewer's yeast, and sugar.

Add warm milk, soft butter, and egg yolk to the dough.

Knead well until a homogeneous consistency is obtained.

Cover the dough with a cloth and let it rise for 30 minutes.

Roll out the dough on a floured surface until it is about 1/2 cm thick.

Cut the dough into triangles and roll them into brioche shapes.

Place the brioches on a baking sheet lined with parchment paper and let them rise for an hour.

Preheat the oven to 200 degrees Celsius.

Bake the brioches in the preheated oven for about 25 minutes or until golden brown.

Once cooked, cut the brioches horizontally and fill them with orange marmalade.

Brush the brioches with marmalade for a shiny and tasty finish.

Serve the jam-filled brioches warm or at room temperature.