In a large saucepan, bring the wine to a boil. Add the mussels. Cover and cook for about 5 minutes, stirring occasionally, until the mussels have opened. Remove the mussels from pan and scatter on a plate. (This allows them to cool quickly and stops the cooking). Remove and discard any that remain closed. Shell the mussels. Set aside.
Pass the cooking juices through a fine sieve. There should be 500 ml (2 cups) of liquid, otherwise add chicken broth as needed. Set aside.
In the same pan, soften the onion in the butter. Add the cauliflower, potatoes, milk and reserved cooking juices. Season with salt and pepper. Bring to a boil. Cover and simmer gently for about 15 minutes or until the vegetables are tender.
In a blender, purée the soup until smooth. Return the soup to saucepan with the cream and mussels. Reheat thoroughly and adjust the seasoning.
In a skillet, brown the croutons in the butter. Season with salt and pepper.
Ladle the soup into four bowls. Garnish with croutons and herbs.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.