Add the clams, cover and cook just until most of them open, about 5 minutes. Add snapper and shrimp, cover and simmer until they are cooked through and the remaining clams have opened, about 2-3 minutes.
5 Using a slotted spoon, transfer the seafood to bowls. Add the butter and parsley to the pot and cook over moderate heat for 1 minute, swirling the pan. Spoon the broth over the seafood and serve with sourdough toast.