What is the name of the Thanksgiving side dish made with green beans and mushroom soup?

The Thanksgiving side dish made with green beans and mushroom soup is green bean casserole.

The classic version combines green beans, condensed cream of mushroom soup, milk, seasonings, and crisp fried onions. It is baked until hot, then finished with another layer of onions for its signature crunchy topping.

Dorcas Reilly developed the recipe in 1955 while working in Campbell Soup Company’s test kitchen in Camden, New Jersey. It was originally called “Green Bean Bake” and was created as a quick recipe using familiar pantry ingredients. Campbell’s later printed it on soup-can labels, helping spread it nationwide.

The dish is sometimes confused with other vegetable casseroles, but mushroom soup and fried onions distinguish the traditional recipe. Fresh beans, homemade mushroom sauce, and alternative toppings are now common variations, while the canned-soup version remains a Thanksgiving classic.