Toasting brings out the rich flavor of hazelnuts, and it's the easiest way to remove their sometimes bitter skins. Follow these steps.
Toast in a 350° F oven, tossing once, until the nuts are golden and the skins begin to split, 12 to 15 minutes. Let cool for 5 minutes.
Skin by transferring to a kitchen towel and rubbing vigorously to remove the papery dark brown layer, which will cling to the towel. Let cool completely.
Store in an airtight container for up to 2 weeks or in the freezer for up to 1 month. Chop and sprinkle over salads, roasted vegetables, or your morning oatmeal. Or use to top muffins (before baking).