But while the requisite or acceptable species for a bouillabaisse remain uncertain, it is clear that the wider the variety of fish, the more interesting the result. Moreover, it is important to achieve a balance between white fish, e.g., snapper, whiting, and sole, and somewhat richer varieties, such as redfish and striped bass. I find that monkfish, a species that may be thought of as Mediterranean but is generally available here, works particularly well. I also like to use shrimp; additional shellfishes, prescribed by some commentators, are optional. In any case, start with whole fish whenever possible, as they are likely to be fresher than ready filets, and you'll need the bones for stock.
The rouille, a spicy garlic mayonnaise, is an essential component of this dish. I like to add a spoonful to each bowl before serving, and pass the rest at the table with a baguette.
Cut the filets into chunks and marinate for several hours in 2 cloves minced garlic, 3 tablespoons of olive oil, and a pinch of saffron.
Chop the onion, leeks, celery, and fennel and sauté with the saffron in olive oil. Add the tomatoes, the remaining garlic, the bouquet garni, orange zest, fennel seed, and stock, and simmer for 1 hour. Remove most of the solids with a slotted spoon.
Fifteen minutes before serving, bring to a boil, add the richer fishes, cook for five minutes, add the remaining fish, and cook 5 minutes more. Add the tomato paste and liqueur for the final 5 minutes. Pour into a tureen and sprinkle with parsley. Place a toasted slice of bagurtte covered with a dollop of rouille on the bottom of each bowl before filling with soup. Serve with remaining bread and rouille.
Peel and slice the onion. Sauté it with the fish bones and heads in butter and oil. Add the remaining ingredients and simmer for one hour.
Trim the crust from the bread, soak it in milk, and squeeze out most of it. Mince the garlic and salt to a paste. Beat the egg yolks in a bowl and mix in the bread and garlic. Add the oil slowly, whisking continually, to form an emulsion. Add tabasco to taste (the sauce should be quite hot).