Heat the butter in a large pot over medium heat. Add the fennel, leeks and celery. Season with salt and pepper. Cook until vegetables are starting to wild.
2
Add the cauliflower to the pan. Stir frequently and cook until cauliflower is just starting to become tender.
3
Add the mussel broth and potatoes to the pot. Bring to a simmer and cook until the potatoes are tender.
4
Puree the soup in a blender. Be careful to fill the blender only half full at a time with the hot soup. Add a small amount of water to the soup if necessary to achieve the desired consistency.
5
Pick the meat out of the mussels reserved from making broth, use them to garnish the soup.
Broth
6
Heat the butter in large sauce pan. Add the celery, onion and garlic. Season with salt and pepper. Cook over med-low heat until the vegetables are are starting to wilt and become translucent.
7
Add the mussels to the pan. Stir to coat in the butter and vegetables. Add the wine and bay leaf. Turn the heat to med-high.
8
Once the wine has come to a simmer, add the water and stir well. Cover the pot and cook until the mussels have opened.
9
Strain the broth through a fine mesh strainer. Set the mussels aside to cool.