1. Peel and roughly chop the shallot. Slice the celery and fennel. Place shallot in the bowl fitted with the ultrablade knife. Launch at speed 10 for 10 seconds; scrape shallot toward the center. Launch for another 10 seconds.
2. Replace the ultrablade knife with the mixer. Add celery, fennel and oil. Launch the P1 simmer program at 270°F for 2 minutes. Add wine and launch the simmer program at 270°F for another 3 minutes.
3. Cut the fish in 1-inch pieces. Add fish, carrots and chicken broth. Season with salt and pepper. Launch the P2 simmer program at 210°F for 20 minutes.
4. At the end of cooking, gradually stir about half the broth mixture into the sour cream, whipping cream and saffron. Add to the bowl and heat at speed 1 at 200°F for 5 minutes.