Divide the dough into two equal parts. Each aprox. 485g.
Grease two eight or nigh-inch pans and line with parchment paper.
Roll each piece of dough over a lightly floured work surface into a 12x14-inch rectangle.
Spread half the Nutella over the dough using an offset spatula.
Roll the dough into a spiral log starting from the long side.
With the log seam side down, cut it vertically in the middle using a sharp knife.
Gently twist the two sides around each other.
Gently lift the log and place it in the prepared pan. Repeat this process with the second piece of dough.
Brush the loaves with the egg wash and sprinkle with the streusel.
Set aside in a warm spot to rest for the second rise, about 90-120 minutes. No need to cover the loaves.