Chop the celery, onion, fennel, and garlic finely. Set aside 1 piece of fennel for garnish. Sauté in a large pot, let it stew well and deglaze with white wine. Add broth and bring to a boil until the vegetables are tender. Once they are tender, add the mussels and let cook for another 3-4 minutes until the mussels open.
Finely chop the reserved piece of fennel and mix the mustard into the cream, season with pepper and salt.
Place a large sieve over another large pot and carefully pour the cooking liquid, mussels, and vegetables into it. This way, you catch the cooking liquid in the large pot and can remove the mussels from the shells.
Once the mussels are out of the shells, they go together with the vegetables into the cooking liquid to mix together, so make sure no shells go in.
Mix well until everything is finely and smoothly blended. Season and strain.
Serve the soup in glasses or cups and finish with mustard cream, finely chopped fennel, parsley, and saffron strands.
Tips
No extra tips needed, Just Enjoy!