Fumet:
Combine the fish trimmings, onion, carrot, celery, leek, garlic, parsley, bay
leaf, thyme, water, and salt to taste in a large soup pot or saucepan and bring
to a simmer over medium heat. Skim off all the bitter foam that rises Continue
to skim until no foam remains, then cover, reduce heat, and simmer 15 minutes.
Add the wine and simmer 15 minutes, covered. Remove from the heat and strain at
once through a fine sieve or a strainer lined with cheesecloth Don’t cook any
longer than this, or the fumet will be bitter You can keep the fumet for a day
in the refrigerator
Soup:
Heat the olive oil in a large heavy-bottomed soup pot or casserole and sauté the
onion with the garlic until the onion is tender. Add the tomatoes, tomato paste,
dried basil (fresh basil goes in later), and thyme and simmer 15 minutes. Add
the fumet, bay leaf, and salt to taste. Bring to a simmer and cook, uncovered,
for 30 minutes. Add the potatoes, cover, and simmer 10 to 15 minutes (you cover
the soup now because you want to cook the vegetables without letting any more of
the liquid evaporate) or until the potatoes are cooked through but still have
some texture. Add the zucchini, corn, and basil if using fresh; cover and simmer
1 5 minutes or until the zucchini is tender. Add pepper and cayenne and adjust
seasonings, adding salt, garlic, or more herbs if you wish. At this point you
may remove the soup from the heat and let it sit until shortly before serving,
when you will bring it back to a simmer and cook the fish.
While the stew is simmering, prepare the mussels. Clean them well in several
rinses of cold water). Bring the wine and water to a boil in a large lidded pot
and add the mussels or clams Steam 5 minutes or until the shells open, shaking
the pan once to distribute evenly. Remove from the heat, drain, and set aside.
Discard any that have not opened.
Fifteen to 20 minutes before serving, bring the soup to a simmer and add the
orange zest and saffron Adjust seasonings and add water if the broth seems too
thick or if there’s not enough of it to cover the seafood. If you add water,
adjust the seasonings again. Add the fish, cover, and simmer 10 minutes, until
the flesh is opaque and falls apart. Serve at once, garnishing each bowl with
mussels or clams, chopped fresh parsley, and a lemon wedge.