Https://youtu.be/Bg2Q8KcGkMQ

Combine flour, sugar, salt, and yeast in a large bowl. Add egg and lukewarm milk. Mix until it becomes a dough.

Knead the dough for 2 minutes. Then add the softened butter and knead until it is fully incorporated. It will be messy at first but as long as we keep kneading, the dough will become less greasy and easier to handle. Knead for 8 minutes or until it becomes smooth, elastic, and not sticky.

Shape into a dough ball. Grease it with some vegetable oil and place in a large bowl. Cover the bowl and let sit for about 1 hour.

Transfer the dough onto a worksurface. Using a rolling pin, roll it into a 3/16-inch (5 mm) thick rectangle.

Spread hazelnut chocolate spread / nutella throughout the surface but leave 1/2-inch (1.25 cm) of the short edge bare. Brush the bare edge with water.

Starting from the opposite edge, roll the dough until the end to form a log. Using dental floss or a serrated bread knife, slice the log into 12 equal-sized pieces.

Arrange them on a baking tray. Cover and let sit for 30 minutes.

Brush each with egg wash (whisk 1 egg with 1 teaspoon of water). Top each with chopped hazelnuts. Bake in a preheated oven at 350°F (180°C) for 20 minutes or until golden brown. Let cool on a wire rack.