This one is for a special occasion! You make a simple stuffing of mostly crab meat, fold fillets of sole over the filling, and poach. When it's done you reduce the cooking liquid and enrich it with lobster stock and butter.
A paupiette is just a thin fillet of fish or piece of meat filled with something savory. They are typically braised or baked in wine or stock. They're very popular in France, and you can often buy them ready-to-cook.