This recipe is vague on the subject of what fish to use. I asked my fishmonger for mixed fish for a stew: he gave me various fillets, and an incomprehensible answer when I asked what they were. I am a little vague, too, about the quantity of stock. About 1.5 litres is my guess, arrived at later after pouring that amount of water into the same saucepan.
This stew serves eight, easily.
For the stock
Fish offcuts and heads (ask a fishmonger -- mine charged me £1 for a bagful)
Dark green parts of three leeks and of a bunch of spring onions, washed
Stalks and fronds of a fennel bulb
Stalks of a handful of flat-leaf parsley
2 sticks celery
8 garlic cloves
For the stew
1.5 kg mixed fish fillets, cut into pieces about three times the size of a forkful
2 onions, roughly chopped (ie, into chunks rather than fine pieces)
White and pale green parts of three leeks, sliced into fork-sized pieces
White and pale green parts of bunch of spring onions, roughly chopped
3 garlic cloves, chopped
1 fennel bulb, roughly chopped
4 sticks celery, roughly chopped
125 ml white wine
2 bay leaves
500 g carton passata
Zest of 1 orange
1.5 l fish stock
450 g new potatoes, boiled and sliced
Handful flat-leaf parsley, chopped
1 heaped tsp saffron fronds
Prepare the stock. Cover the fish offcuts in cold water in a stock pot, bring to a simmer, skim off the surface froth, and throw in the vegetables. Cook on a very low light for about 40 minutes. (It is said that overcooked fish stock is bitter.) Sieve, return the stock to a pan, and simmer until reduced to about 1.5 litres.
Meanwhile, choose a large saucepan or casserole. I used a 28 cm, oval Le Creuset; the stew filled it almost to the brim. Pour a layer of oil into the bottom, and throw in all the vegetables (except the cooked potatoes), cooking them over a low to medium heat until they start to turn golden. Pour in the wine, and allow it to bubble for a couple of minutes. Add the bay leaves, passata, orange zest, and salt to taste. Simmer until reduced and thickened.
Have your stock simmering in a saucepan. Turn up the heat under the stew, and pour in the stock. This is how you're supposed to make a bouillabaisse, liaising the stock and the vegetable mixture. You'll be surprised at how thick the sauce remains. Let it simmer for five minutes or so. Throw in the cooked potatoes, and bring back to a simmer. Check the seasoning.
Submerge the fish in the stew. Cook for five minutes longer. Check the fish: it should be ready. Turn off the heat, and stir in the parsley and saffron.
I served the stew with boiled Camargue rice, which has pleasingly plump and absorbent grains.