Add flour, some milk, sugar, butter, egg, fresh yeast, and salt to a bowl. Beat slowly at first until everything is well mixed. Then knead well until the dough is no longer sticky and becomes smooth. Set aside for approx. 30 min.
Meanwhile, add the remaining milk, sugar, and ground cinnamon to a pot. Bring to a boil. Stir in ground hazelnuts. Remove from heat and pour the content into a bowl. Let cool in a fridge.
Pre-heat oven to 160°C/320°F. Dust the work surface with some flour. Roll out the dough into a 40 x 50cm/16 x 20 in. rectangle. With a palette knife, spread the nut filling onto the dough.
Roll up the dough along the width. Slice the dough along the length in half. Braid the two long logs carefully.
Place the braided bread onto a lined baking sheet. Cover with a kitchen towel and set aside for approx. 30 min.
Bake the bread at 160°C/320°F for approx. 35 min.
Sift confectioner’s sugar into a bowl. Add water to create a frosting. Brush the frosting onto the warm bread. Enjoy!