Warm 600 ml of whole milk until lukewarm, then whisk in active dry yeast, 15 g of powdered sugar, and 10 g of all-purpose flour.

Rest the yeast mixture for 10 minutes until foamy and expanded.

Combine the remaining all-purpose flour, remaining powdered sugar, salt, egg, and egg yolk in a large mixing bowl.

Pour in the activated yeast mixture and 200 ml of vegetable oil.

Knead the dough until smooth and elastic, keeping the dough slightly sticky.

Oil a second large mixing bowl and transfer the dough into it.

Cover the dough with plastic wrap and let it rise in a warm place for 60 minutes.

Line the baking tray with parchment paper and lightly oil the work surface.

Divide the risen dough into 20 equal balls and roll each ball into a small oval.

Spread about 20 g of chocolate hazelnut spread onto each oval, then roll it into a bun.

Place the buns seam-side down on the lined baking tray and cover them with a clean kitchen towel.

Rest the shaped buns for 20 minutes while the oven heats to 200°C.

Brush the buns with 25 ml of vegetable oil and bake them at 200°C for about 20 minutes.

Remove the buns when golden brown and cool them briefly before serving.