Sour Cabbage Flunder Soup

The soup you are referring to is likely called "Sour Cabbage Soup with Flounder," also known as "Sourkraut Fish Soup" in some restaurants in the United States. This soup features flounder, a type of flatfish, as the main protein, and sour cabbage, also known as sauerkraut, as a key ingredient.

Sourkraut Fish Soup is a traditional Eastern European dish, particularly popular in countries like Poland, Russia, and Ukraine. The soup is known for its tangy, sour taste, which comes from the fermented cabbage, and its hearty, satisfying consistency.

The soup typically also includes other vegetables, such as carrots, onions, and potatoes, as well as seasonings like black pepper, bay leaves, and sometimes dill. The flounder is usually added in chunks and cooked until tender.

Sourkraut Fish Soup is often served hot, garnished with fresh herbs and a dollop of sour cream. It's a distinctive and flavorful dish, and a great option for those who enjoy hearty, savory soups.