Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   8      pounds        mussels -- scrubbed and
                        -- debearded
                        flour
   4      ounces        unsalted butter
   1      pound         fresh young sorrel -- * see note
   2      cups          dry white wine
   2      medium        onions -- finely chopped
   4                    garlic cloves -- minced
     1/4  cup           parsley -- finely chopped
   4                    egg yolks
   1 1/3  cups          creme fraiche -- or heavy cream
   1      dashes        cayenne pepper
   1      dashes        freshly grated nutmeg
   2      teaspoons     lemon juice
                        salt and fresh ground pepper

Preparation:

* well rinsed, tough stems removed, leaves very coarsely chopped. 1. Place the scrubbed mussels in a large bowl, cover with cold water and stir in 2 or 3 large handfuls of flour. Refrigerate for at least 4 hours or overnight; while the mussels feast on the flour, becoming plumper and more succulent, they will also disgorge sand and excess salt. After soaking, scoop the mussels up out of their dirty soaking water and rinse them thoroughly under cold running water. 2. In a large non-aluminum skillet, melt 2 tablespoons of the butter over moderate heat. Add the sorrel and cook, stirring, until wilted, about 1 minute. Continue to cook , turning the sorrel in the butter and pressing and mashing the leaves with a heavy spoon, until they have melted into a loose but tender puree, 5 to 10 minutes. Remove from the heat and let cool to room temperature. (The sorrel purée can be cooked 2 or 3 days in ahead and refrigerated, or frozen up to 2 months.) 3. Put the mussels in a large non-corrodible flameproof casserole or stockpot. Add the wine, onions, garlic, parsley and remaining 6 tablespoons butter; stir to mix well. Cover tightly and bring to a boil over high heat. Cook, shaking the pot vigorously once or twice, until all the mussels open, 5 to 7 minutes. 4. Using a slotted spoon, transfer the mussels as rapidly as possible to a large warmed bowl. Cover to keep warm. 5. Strain the mussel broth from the casserole through several thicknesses of dampened cheesecloth or a fine mesh sieve. In a large bowl, whisk together the egg yolks and creme fraiche until blended. Gradually beat in the hot broth in a thin steady stream. Rinse and dry the casserole and pour the hot sauce back in. 6. Set the casserole over low heat and whisk the sorrel puree into the sauce. Add the cayenne, nutmeg and lemon juice; season with salt and black pepper to taste. Cook, stirring for 2 to 3 minutes until the sauce is hot and slightly thickened. 7. Pour the sauce over the mussels and then tip the contents of the bowl back into the pot. Serve immediately, ladling the mussels and their lovely sauce into heated soup plates and passing a big basket of crusty bread. The Best of Food and Wine, 1988