A grilled cheese (sometimes known as a toasted sandwich or cheese toastie) is a hot sandwich typically prepared by heating one or more slices of cheese between slices of bread, with a cooking fat such as butter or mayonnaise on a frying pan, griddle, or sandwich toaster, until the bread browns and the cheese melts. History The cheese dream, an open-faced grilled cheese sandwich, became popular in the U.S. during the Great Depression. U.S. government cookbooks describe Navy cooks broiling "American cheese filling sandwiches" during World War II. Preparation A grilled cheese sandwich is made by placing a cheese filling, often cheddar or American cheese, between two slices of bread, which is then heated until the bread browns and the cheese melts. A layer of butter or mayonnaise may be added to the outside of the bread for additional flavor and texture. Alternatives may include additional ingredients, such as meat, peppers, tomatoes, or onions. Methods for heating the sandwich include cooking on a griddle, fried in a pan, or using a panini grill or sandwich toaster, the latter...