Heat the O California Organic Extra Virgin Olive Oil in a large pot, and cook the onion, celery, carrot, and squash for 5 minutes, or until lightly browned. Pour in enough of the chicken stock to cover the vegetables. Bring to a boil. Reduce heat to low, cover pot, and simmer 40 minutes, or until all vegetables are tender.
Transfer the soup to a blender, and blend until smooth. Return to pot, and mix in any remaining stock to attain desired consistency. Season with salt and pepper. Drizzle the O Sherry Vinegar just prior to serving.