This is how we prepare brodetto.
Clean the fish and cut into largish chunks. Clean the mussels and prawns but do not shell the prawns. Discard any mussels that are damaged or open. Clean the squid and slice finely.
Fry the onion and garlic in olive oil in a shallow pan (preferably one with two handles) until golden. Add the squid to the pan and cook for 3–4 minutes. Stir in the chopped tomatoes, wine and a few drops of vinegar, the tomato coulis or passato and
Serve sprinkled with the rest of the parsley and bread toasted on the griddle.