[Sauced Mussels Served in Scallop Shells]
This is a more formal recipe for mussels. They are steamed open with wine and flavorings, then a rich, creamy, buttery sauce is made with their cooking liquid. This is the same heavily buttered sauce parisienne found, but with a quite different flavor. If the mussels are served on the half shell, as they often are in Brittany, they are called mouclades. We have suggested in the following recipe that they be shelled, sauced, and served in scallop shells; done this way they may be prepared ahead of time. There are naturally many versions and flavorings for mussels served in a sauce. For instance, if you omitted the curry, garlic, and fennel in the recipe, and substituted ½ cup of mushroom stems, your mussel dish would be à la poulette. Also, if you omitted the special flavorings, and the cream, egg yolks, and butter enrichment, then stirred a cup of béarnaise sauce into your velouté just before serving, you would have moules à la béarnaise.