This is the famous Bouillabaisse from Marseille and its environs. It is hard to get a truly authentic Bouillabaisse in the south of France and even harder to get it elsewhere. This one is adapted to the United States. A lot of the fish in the original dish like conger eel and rascasse is very difficult to find here. However: with a little imagination and ingenuity one can come very close to the taste and the spirit of this marvelous dish. It is usually served with a sauce called 'Rouille' meaning 'rust'. It is a mayonnaise based garlic sauce with a little saffran or tomato paste mixed in. Hence the name rust for the color. If you tell anyone from Marseille that the 'Rouille' is made from mayonnaise the will tell you it is made with potatoes and garlic. They would be right of course but it is easier to make it with mayonnaise. Just don't tell the Frenchman.
42 minutes ago