Preheat the oven to 350 degrees Fahrenheit. Line a cookie sheet with parchment paper.
Roll out one can of crescent dough onto the cookie sheet. Roll it into a 12 inch long rectangle. Then cut off the corners to cut it into a 10 inch circle. (A plate, cake pan, etc in those sizes can help cut the edges smoothly).
Spread about 1/4 to 1/3 cup of Nutella onto the dough.
Repeat rolling out, cutting, and spreading Nutella with two additional cans of crescent roll. Placing them on top of one another to create 3 layers.
Roll out and cut the last can, and place it on top of the others.
Place a 2 to 3 inch cup onto the center of the dough.
Then use a sharp knife to cut the dough into 16 even wedges.
Take two sections that are next to each other and twist them away from each other, about 3 times. Pinch the edges together to make a star point.
Repeat with the remaining sections, twisting them two at a time.
Add your egg and water to a small bowl and whisk them together.
Brush the egg wash evenly over the top of the dough with a silicone brush.
Bake the star bread in the oven for 25 to 30 minutes or until the top is golden and it is cooked throughout.
Let it cool for 5 to 10 minutes.
Dust the top with powdered sugar and serve.