In a mixing bowl, combine lukewarm milk, sugar, and dry yeast. Let it sit for 10 minutes until frothy.

Add melted butter, flour, and salt to the yeast mixture. Knead until a smooth dough forms, about 10 minutes.

Cover the bowl with a kitchen towel and let the dough rise in a warm place for 1 hour or until doubled in size.

Preheat the oven to 180°C (350°F).

Roll out the dough on a floured surface into a rectangle about 1 cm thick.

Sprinkle the chopped chocolate evenly over the dough and roll it up tightly from the long side.

Cut the rolled dough into 12 equal pieces and place them on a baking sheet lined with parchment paper.

Brush the tops of the rolls with the beaten egg.

Bake in the preheated oven for 20 minutes or until golden brown.

Let cool slightly before serving.