Onion soups have been popular at least as far back as Roman times. They were, throughout history, seen as food for poor people, as onions were plentiful and easy to grow. The modern version of this soup originates in France in the 18th century, made from beef broth, and caramelized onions. It is often finished by being placed under a grill in a ramekin traditionally with croutons and gruyère melted on top. The crouton on top is reminiscent of ancient soups.