A hazelnut is a small, round nut with a smooth, hard brown shell and a sweet, rich flavor inside. You've probably tasted hazelnuts in chocolate spreads, cookies, or trail mix. The nut grows on hazel trees, which are native to Europe and Asia but now grow in many parts of the world, including Oregon, which produces most of America's hazelnuts.

Inside the hard shell is a cream-colored kernel that tastes slightly sweet and buttery. People eat hazelnuts raw, roasted, or ground into flour or paste. Roasting them brings out their flavor even more. In Europe, hazelnuts are often paired with chocolate, and in Turkey, they're considered so important that the country grows about three-quarters of the world's supply.

The hazelnut tree has been important to humans for thousands of years. Archaeologists have found hazelnut shells at ancient campsites, showing that people were cracking them open and eating them long before farms or cities existed. Today, squirrels still gather and hide hazelnuts each fall, sometimes forgetting where they buried some, which helps new hazel trees grow in unexpected places.