Line a bread pan with two sheets of parchment paper, one crosswise and one lengthwise. Allow the paper to overlap the pan's edges; this will make removing the baked bread easier.

In a small bowl, stir together the nutella and the cinnamon. Set aside.

On a floured surface, roll the dough out into a 10"x 16" rectangle. Using an offset spatula or large spoon, spread a thin, even layer of the nutella onto the surface of the dough. Leave a 1" margin along one long side (on the edge farthest away from you) of the dough to allow for sealing.

Fold over a 1/2" of the long side go the dough and continue to roll the dough away from you (as if you are rolling cinnamon rolls). Make sure to roll the dough tightly and press down slightly to pack the roll. This will prevent the baked dough from falling apart when sliced.

Brush the uncovered margin of dough with a light coating of egg wash, and finish the roll with a pinch to seal the seam.

Using a very sharp knife, or razor blade, slice the dough in half, lengthwise. Try not to move the pieces from where they are. Pinch two ends together to connect the pieces of brioche. Begin to twist the dough from one end to the other. Carefully, bring the ends of the dough together so that your dough is now in a horseshoe, or looped, shape. Pinch the two ends together and twist this to form a larger rope shape.

Carefully, transfer the dough to the prepared pan (it's okay if it's messy). Brush lightly with the egg wash. Cover with a clean towel and allow to rise in a warm, draft-free area* for 45 minutes-1 hour or until doubled in size.

While your dough is rising, preheat an oven to 375°F. Once the dough has risen, brush the surface again with egg wash and bake for 25-30 minutes. If the dough begins to brown too quickly, cover it lightly with a piece of foil. Bake until golden brown or until it sounds hollow when tapped. Remove from the oven and allow to cool.

Once cooled, slice and enjoy!

*see note