Hazelnuts, or filberts, come from a number of similar trees in the genus Corylus that are native to Europe, Asia, and the continental U.S. The nuts are small and round, and have a distinct, fairly strong flavor.

Hazelnuts have been cultivated since antiquity and were eaten before the dawn of agriculture. They have long been popular in Europe as the nut of first resort, much like the walnut has been to Great Britain and the pecan to the southern U.S. Correspondingly, hazelnut liqueurs, coffees, confections, and baked goods are available in Europe in innumerable variety. In the U.S., hazelnuts suffered a period of unfashionability in the early 20th Century, and were encountered mostly as an ingredient in mixed nut assortments, either shelled or unshelled. Recently, however, the popularity of the German hazelnut spread Nutella has risen in parallel with other domestic uses of the hazelnut, such that they are even seen in traditional confections such as pralines.