In a large saucepan over medium heat, saute the celery, onion and carrot in olive oil for 5 minutes, or until onion is translucent. Remove from heat and set aside.
Steam cauliflower in a colander over boiling water or in a steamer until tender. Mash.
Add the mashed cauliflower to the vegetable mixture, return to stovetop over medium heat and add the chicken broth. Pepper to taste and simmer for 15 minutes or until soup is heated thoroughly.
