In this riff on bouillabaisse, pasta shapes are added to the broth just before the dish is served. Like the Provencal classic, the seafood stew has multiple layers of flavor and a saffron note. But because it calls for one kind of fish -- firm-fleshed black bass -- instead of several, it's far easier to make. Ask your fishmonger to fillet the fish, reserving the head and bones of one for the broth. Serve the stew with our Parsley-Aioli Crostini.