For the Mussel Soup:
2 tablespoons unsalted butter
2 tablespoons extra-virgin olive oil
2 medium onions, thinly sliced
1 large fennel bulb, trimmed and thinly sliced
2 stalks celery, peeled, trimmed and thinly sliced
1 medium leek, white and light green parts only, thinly sliced, rinsed and dried
1 large carrot, thinly sliced
1 large Idaho potato, peeled and cut into
small pieces
4 cups unsalted chicken stock
1 cup heavy cream
Large pinch of saffron threads
Sachet (1 teaspoon each fennel seeds, coriander seeds, and white peppercorns, 1 bay leaf, 2 sprigs thyme, and
4 sprigs flat-leaf parsley, tied in cheesecloth)
Salt and freshly ground white pepper
For the Crust:
3/4 cup fresh bread crumbs
1 stick plus 2 tablespoons unsalted butter, at room temperature
2 tablespoons finely chopped flat-leaf parsley leaves
4 cloves garlic, finely chopped
1 tablespoon finely chopped toasted almonds
1 tablespoon finely chopped speck ham or prosciutto
Salt and freshly ground white pepper
Preparation
1. Melt the butter in a Dutch oven or large pot over medium heat. Add the shallots and cook, stirring, just until translucent, about 5 minutes. Increase the heat to high and add the mussels and white wine. Season with pepper. Cover and cook, stirring a few times, until the mussels open, 3 to 4 minutes.
2. Meanwhile, place a cheesecloth-lined sieve over a large bowl. When all the mussels have opened, turn the mussels and liquid into the sieve. Reserve the mussels and broth separately. When the mussels are cool enough to handle, remove the meat from the shells. Discard the shells and cover the mussels (refrigerate them if you are not making the soup right away).
Make the Mussel Soup:
3. Melt the butter with the oil in a large pot over medium-high heat. Add the onions and cook, stirring, just until translucent, 5 to 7 minutes. Add the fennel, celery, leek, carrot, and potato and cook until tender, 15 to 20 minutes. Add the heavy cream, saffron, sachet, reserved mussel liquid, and chicken stock, and season with salt and pepper; bring to a boil. Reduce to a simmer and cook, skimming regularly, until all the vegetables are tender, about 20 minutes.
4. Working in batches, purée the soup in a blender. Push the purée through a fine-mesh sieve set over a bowl, then season to taste with salt and pepper. (The soup can be kept covered in the refrigerator for up to 4 days or frozen for a month.) Bring to a boil before serving.
To Make the Crust and Gratins:
5. Mix together the bread crumbs, butter, parsley, garlic, almonds and ham in a bowl until blended. Season with salt and pepper. Roll out the mixture between two pieces of parchment paper to form a 4-inch square that is about 1/4-inch thick. Transfer the packet to a small baking sheet and freeze for at least 30 minutes, then cut the crust into four squares; refrigerate until needed.
6. Preheat the broiler. Butter a large gratin dish. Put a 2-inch cake ring or biscuit cutter in the gratin dish and fill with one-fourth of the mussels. Lift off the ring and top the mussels with a square of crust. Repeat to make 3 more mussel gratins. Broil the gratins-watching closely-for 2 to 4 minutes, until the tops are golden brown.
To Serve
Bring the soup to a boil. Transfer each gratin to the center of a warm soup bowl. Ladle the hot soup around the mussels and serve immediately.
Reprinted from: Daniel's Dish: Entertaining at Home with a Four Star Chef, Daniel Boulud, Filipacchi Publishing, 2003
15 minutes 
