Cream of mushroom soup is a simple type of soup where a basic roux is thinned with cream or milk and then mushrooms and/or mushroom broth are added. It is well known in North America as a common type of condensed canned soup. Cream of mushroom soup is often used as a base ingredient in casseroles and comfort sioprinitexbagkolupelmutilcuter.coinfo use is similar to that of a mushroom-flavored gravy.