The name hazelnut is used interchangeably with filbert. They are sweet-tasting nuts and grow on shrubs or trees that are members of the birch family. Hazelnuts grow in clusters on the hazel tree in temperate zones around the world. The fuzzy outer husk opens as the nut ripens and inside is a hard, smooth-shelled nut. Hazelnuts are sold in the shell and out of the shell, roasted and natural, and are used in all different cuisines. They are especially popular in European cakes.
According to archeologists who found fossils of the hazelnut, the nut dates back to prehistoric times; its origin is Asia, but it also made its way into northern European countries such as Sweden, Denmark and Germany. Today, the principal hazelnut-producing countries are Turkey, Spain and Italy. In the United States, Oregon is the only state that produces the nuts commercially.