Warm the 200 ml whole milk until lukewarm, about 35–40°C; it should not feel hot.

Pour the warm whole milk into the large mixing bowl and stir in the active dry baker's yeast.

Add the 60 g granulated sugar, 2 eggs, and 1 g salt to the bowl.

Mix the ingredients until the eggs are fully combined with the milk mixture.

Add the 500 g wheat flour gradually to the bowl and mix until a shaggy dough forms.

Knead the dough for about 8 minutes until smoother and elastic.

Add the 100 g softened unsalted butter in small portions and knead until fully incorporated.

Cover the dough with the clean kitchen towel and let it rise until doubled in size, about 60 minutes.

Press the risen dough gently to remove excess gas and divide it into 10 equal portions.

Roll each dough portion into a disk about 5 mm thick.

Place about 15 g Nutella hazelnut cocoa spread in the center of each dough disk.

Pinch the dough edges together to seal the filling and shape each portion into a smooth ball.

Arrange the filled buns seam-side down on the baking tray and cover them with the clean kitchen towel.

Let the buns rise for 30 minutes while preheating the oven to 180°C.

Brush the tops of the risen buns with 1 egg yolk for a glossy finish.

Bake the brioche buns at 180°C until puffed and golden brown, about 15 minutes.

Cool the buns for at least 10 minutes before serving so the filling is not dangerously hot.