If you purchase a whole fennel, chop off the top woody portion. Split the fennel bulb in half from the top to the root. Take one half of the fennel and remove the woody root tip with a paring knife. Repeat on the second half of the fennel bulb. Chop the fennel into bite sized pieces. Wash in a colander and set aside. Wash and chop remaining vegetables and set to the side.
In a large soup pot, heat one tablespoon oil over a medium high flame. Add vegetables and sauté about 3 to 5 minutes. Add broth/stock along with salt and pepper to taste. Allow the soup to come to a simmer, then reduce the heat to medium low and cover. Cook for 20 minutes or until the vegetables are tender. Blend soup in batches until smooth, or leave some of the vegetables in small chunks.
When the soup is cooked, add parsley and serve.
NOTE: The top of the fennel can be used for broth.