What is the traditional main ingredient of Mock turtle soup?

The traditional main ingredient of Mock Turtle Soup is calf's head.

While the name might suggest turtle meat, the soup actually gets its name from the fact that calf's head meat has a texture similar to turtle meat, and it was often used as a less expensive substitute. The soup is typically made with a rich, flavorful broth, vegetables like carrots, onions, and celery, and often includes ingredients like tomatoes and herbs to enhance the flavor.