Toasting hazelnuts is relatively simple, there's just a few things you have to watch out for. Hazelnuts, once its outer shell is removed, have a thin dark skin surrounding the nutmeat. This can be removed after they are toasted in the oven. For best results, place the hazelnuts loosely in a single layer on a baking sheet, then put the sheet in a preheated 350F oven. Bake for seven to ten minutes, watching them closely, as they tend to burn easily, even shaking the sheet several times, until they are fragrant. The nuts will be hot when you take them out of the oven. Place them in a towel, draping the towel over a bowl makes it easier to dump them off the sheet. Cover the nuts with the rest of the towel until they have cooled enough for you to be able to touch them without burning the ends of your fingers. Rubbing the nuts vigorously in the towel for a couple of minutes will separate most of the papery skins from the meat. Open the towel and rub with your fingers those nuts where the skins are tougher to rub off. Some of the skins will stick, no matter how hard you rub, these will still be okay, the toasting removes the bitter tannins, and they add a little colour and depth of flavour to the nuts.