Cut celery, carrots and leek into rounds, fennel and onion into fine slices, chop garlic.
Heat the olive oil and sauté the above in it until soft. Sprinkle with saffron and add soup. Soften the vegetables.
Cut the boned and skinned fish fillets into strips and add to the frying pan. Cook on a low fire. Season strongly with a little salt and freshly ground pepper, bring to the table with the Parmesan cheese and bread cubes.