Line a baking sheet with parchment paper or a silicone mat
On floured surface or on top of parchment paper, roll out the puff pastry into a rectangle
Spread the Nutella all over the surface and sprinkle in the Hazelnuts
Roll tightly on both sides so they can meet in the middle. Dip your finger in water and wet a little bit of the sides of each roll so they can stick together
Slice them into 1/4 inch and place on the cookie sheet. With your hands, flatten them and sprinkle on sugar.