Trim and halve carrots; do not peel. Put in soup pot and add chicken broth to cover. Bring to a boil, lower heat and simmer until the carrots are tender, about 40 minutes. Meanwhile, saute onions and bay leaves in oil until onion is translucent. Reserve. When carrots are tender, place them in a blender. Discard bay leaves; add the onions to the blender. Puree until smooth, adding liquid from the soup pot as needed for consistency. Season with salt and pepper to taste.