I saw this and knew I had to make it.....and I have several times now. It is not as hard as it looks. It taste divine and has a real WOW factor. My directions may be confusing but you can find demonstrations on Youtube and on line elsewhere. Please try it!!
Mix all but the egg whites and the Nutella. Knead on floured board 10 minutes or knead in stand mixer 5 minutes.
Oil a clean bowl and put dough in bowl. Roll dough in oil and cover bowl with plastic wrap and cover and raise until double in size (2-3 hours)
Gently Punch down. Divide in 4 pieces. Roll one piece into a disc slightly larger than a dinner plate. Place plate upside down on the dough, cut around plate and lift round disk onto a parchment lined cookie sheet.
Put about a third of the jar of Nutella in a bowl and warm in the microwave so it spreads better. With an off set spatula, spread Nutella over the disk but leave about a 1/2 inch boarder of clean dough
take another 1/4 section of dough and roll out to plate size, cut out and place on Nutella . Spread with Nutella within 1/2 od edge. Repeat with third disk with more Nutella.
Roll last 1/4 of dough cut and cover the top Nutella covered disk.
Place a smallish drink glass, upside down in the center of the top layer of dough With sharp knife cut from edge of glass to edge of dough at 12, 3, 6 and 9 o'clock positions. Cut those quarters in half and then each section in half again. You should have 16 rays radiating from the center circle. Remove glass.
pick up two "rays" and twist them away from each other for two rotations. Repeat more times. Pinch ends of the two twisted "rays" together.
Put in warm place and rise 30 minutes. Brush bread with egg whites. Bake in 350 degree preheated oven for 15 -20 minutes until golden