Separate 4 tbsp of flour and 2 tbsp of sugar. Warm the milk (not hot) and mix with yeast, reserved flour, and sugar. Cover and rest for 20 minutes until frothy.
Melt the butter and let it cool. Add to the yeast mixture along with the remaining sugar, eggs, and salt.
Gradually add the flour, kneading for about 15 minutes, until the dough becomes soft and elastic.
Grease a bowl with oil, place the dough inside, brush lightly with oil, cover, and leave to rise for 1 hour.
Divide the dough into smaller portions, roll each into a thin round, and cut into triangles (like pizza slices).
Place a spoonful of chocolate spread at the base of each triangle, then roll into a crescent shape, tucking in the ends.
Preheat the oven to 180°C. Place crescents on a baking tray lined with parchment, brush with beaten egg yolk, and bake for 20 minutes, until golden brown.
Serve warm with gooey chocolate inside, or cooled with coffee or milk.