What crisp topping is a main ingredient in green bean casserole?

French fried onion is the crisp topping that became a defining ingredient in green bean casserole.

In the classic version, fried onions are mixed into the green-bean-and-soup filling and added again on top near the end of baking. That two-stage approach distributes onion flavor through the casserole while preserving a crunchy surface. The topping gives the otherwise soft, creamy dish contrast and visual appeal.

Dorcas Reilly created the casserole in 1955 for Campbell Soup Company. Culinary historian Laura Shapiro described the crunchy fried-onion topping as a particularly clever touch because it transformed a simple convenience-food dish into something that seemed more festive. The topping also required no separate onion-frying step when packaged French fried onions were used.

Some newer recipes substitute toasted breadcrumbs, crackers, potato chips, or homemade fried shallots. Those can be tasty variations, but they are not the signature topping of the classic American Thanksgiving casserole. Likewise, almonds may appear in other green-bean dishes, yet they are not the defining crisp ingredient in the traditional Campbell-style recipe.