From Beaneaters & Bread Soup by Lori De Mori & Jason Lowe - this is a classic Tuscan fish stew
Serves 6
500g clams
Salt
2.5kg assorted fish of different sizes, some whole (eg scorpion fish, gurnard, hake, bream, John Dory, grouper, grey mullet, monkfish)
500g large prawns in their shells
500g squid and/or cuttlefish
For the Stock
1 yellow onion, peeled
1 carrot, peeled
1 celery stalk
Handful of flat-leaf parsley
For the Cacciucco
6 tbsp olive oil
1 yellow onion, finely chopped
Handful of flat-leaf parsley, chopped
4 garlic cloves, 3 crushed, 1 peeled
2 dried chillies, crushed
200ml dry red wine
800g canned Italian plum tomatoes, chopped
Sea salt and freshly ground black pepper
6 slices country bread, toasted
To clean the clams, soak in plenty of cold salted water for 2 hours, changing the water several times. Scale, clean and fillet the whole fish, reserving the heads and bones. Cut larger fillets into chunks. Rinse the prawns. Clean the squid/cuttlefish and cut into pieces, discarding the ink sacs.
To make the stock, pour 1.5 litres of water into a stockpot and add the fish heads and bones, onion, carrot, celery and parsley. Bring to the boil, lower the heat and simmer for 40 minutes, skimming often. Discard the onion, celery and parsley, then pass the stock through a mouli (food mill) or press through a sieve. Return the stock to the pot and keep at a low simmer.
To make the cacciucco, heat the olive oil in a large cooking pot and add the chopped onion, parsley, crushed garlic and chillies. Sauté over a gentle heat until soft and fragrant, adding a bit of water to the pan if it dries out.
Add the squid and/or cuttlefish and stir well. Turn up the heat to high, pour in the wine and let bubble until the alcohol evaporates. Stir in the tomatoes and a generous ladleful of the fish stock. Bring to the boil, then lower the heat and simmer for 15 minutes.
Add the fish fillets and pieces with two ladlefuls of stock and simmer for 15 minutes. Adjust the consistency if necessary by adding more stock; the soup should not be too dense. Season with salt and pepper to taste. Add the clams and prawns and simmer, covered, until the clam shells are open and the prawns are pink.
Rub the toasted bread with the remaining garlic cloves. Lay a slice of bread on the bottom of each soup plate. Ladle the cacciucco on top and serve.

You could - and should - get the fishmonger to scale and fillet the fish and prepare the squid for you. Just remember to ask for the heads and bones for the stock.