what to do:
Preheat oven to 350F / 180 C.
Place the hazelnuts in a single layer on a roasting pan. Use parchment or foil.
Roast for 12 to 16 minutes leaving them in the oven until they are aromatic and lightly toasted and the skins have started to crack. After 12 minutes keep a close eye on the hazelnuts because they can burn quickly at this point.
Wait until the hazelnuts and tray are not too hot to the touch and place a kitchen towel over warm hazelnuts. Leave it for about 2 minutes.
Put all hazelnuts in the towel and use the towel to gently rub them. You can also press/roll the hazelnuts on a surface using a circular movement (the surface can be the tray where they baked).