Butternuts are nuts in the Juglans genus, which also includes walnuts. The nuts strongly resemble walnuts, growing in sticky strongly scented pods which split open to reveal a knobbled husk with a shell inside. Butternuts are also sometimes called white walnuts, a nod to their resemblance to conventional walnuts, although they have a far richer, sweeter, flavor and more pale bark and wood. Unfortunately, true butternuts can be very difficult to obtain, because they are not cultivated on a wide scale and the butternut crop has been devastated by canker and fungal infections.
Like other members of the Juglans genus, butternuts have pinnately compound bright green leaves and relatively small flowers, which appear in the late Spring. The nuts mature in the fall, and they are harvested with difficulty, since the shells are so thick. Other parts of the butternut tree are useful as well, including the wood, which is milled for use in fine woodworking. Historically, the sap has been used to make syrup, and the bark has been brewed into beer.
As a dessert ingredient, butternuts are a tasty and unusual treat. They have a rich, creamy flavor which some consumers find quite enjoyable. Recipes for foods like maple nut frosting may call for butternuts, since they complement the flavor of sweets like maple syrup. The high oil content also makes butternuts very popular, since adding butternuts causes a dessert to become very rich. This high oil content can also cause butternuts to go rancid quickly, however, so they should be stored in a cool dry place and used within three to four months.
The trees are native to Eastern North America, where they have been used as a source of food for centuries. Most farmers cultivated small orchards of butternuts for personal use, selling a minimal volume of the nuts and keeping the rest for home cooking. In the 1960s, a serious canker disease began to afflict the American butternut crop, particularly devastating commercial producers since it seems to attack large clusters of trees more quickly. The canker has made butternuts very difficult to obtain, and sometimes very costly as well.
When a recipe calls for butternuts, sometimes other nuts such as pecans or hazelnuts can be used for a similar rich mouthfeel. Using other nuts may change the flavor profile of the dish, but is certainly better than using no nuts at all. People who are having difficulty finding butternuts should try contacting heritage producers on the East Coast of the United States, as they are more likely to have small stands of butternuts which have not been damaged by blight.
