The key to this dish is to leave the heavy lifting to a fish purveyor, who often will steam the shellfish and shuck the oysters for a minimal charge. Make the simple sauces earlier in the day, and your work is done. For the serving tray, buy crushed ice or place a few cups of ice in a plastic bag, wrap in a dish towel, and crush using a rolling pin or a meat tenderizer.
This recipe is adapted from "Pasta Sfoglia," by Ron and Colleen Suhanosky (Wiley, 2009), which also has a recipe for preserved lemons. Serve this dish with nutcrackers, so that guests can work on their own crabs and lobster tails. The job can get messy, so have extra napkins on hand.
Ingredients associated with Mediterranean fish stews -- garlic, fennel, saffron, and seafood -- are brought together in our Provencal potpie, which is served with garlicky aioli; the pie is topped with convenient store-bought puff pastry, whose layers won't overwhelm the lobster, shrimp, bass, and halibut underneath.