Hazelnuts are globe-shaped or oval nuts up to 2cm/1in long with a hard brown shell. They grow in most parts of Britain, but cobnuts (a type of wild hazelnut) are particular to Kent. Most of the world's commercially grown hazelnuts come from Turkey. You may be able to buy fresh hazelnuts - particularly native cobnuts - still in their husks, but most are sold already dried and processed, whole, chopped, or ground, either in or out of their skins.