French Fried Onions are made from small diameter slices of onion that are covered with a batter and then deep fried into small, crisp pieces of onion. The Onions are then most often used as toppings for casseroles or for use in coating foods, similar to a breadcrumb.An onion is a round vegetable with a light brown skin. It has many white layers on its inside which have a strong, sharp smell and taste.