Put the fish, cleaned as usual and cut up if they are at all large, into a casserole and add the other ingredients (except those for the rouille), using enough olive oil to moisten the mixture well, but no more. Cover with boiling water and cook over a vigorous flame until the fish is done. Serve it to each guest on one plate and the soup, poured over a slice of toast, on another.
The dish is accompanied by a sauce called rouille. Pound the garlic and peppers well in a mortar, add the chunk of damp bread and mix thoroughly together. Then add the olive oil and lastly the fish broth (of which you may not need quite as much as is indicated). This sauce, which has the consistency of a mayonnaise, is served separately. Reboul describes it, justly, as a ‘sauce énergique au parfum sui generis’.
The reader will notice that he has not been told precisely which fish to use. This is unnecessary, as people are much more relaxed about aigo-sau than about bouillabaisse. For those who would like suggestions I mention small specimens of sea bass, the bream family or grey mullet.