Marinate the fish in the oil, lemon juice, a couple of tbs of minced garlic and most of the parsley (reserve a little for garnish) for a few hours (4hours) in the refrigerator.
2
Heat some more oil in a large, heavy-based saucepan or clay pot and sauté the remaining garlic, adding the onion after a few seconds. When the onion is lightly colored, add the chopped tomato and cook for 1min. Add the wine and cook for about 5 or less until it loses its acidity.
3
Season the marinated fish with salt and pepper, making sure you get each piece. Add to the pan and stir well, then add the fish stock or water to just cover the fish. Bring to the boil over high heat then continue cooking rapidly for 20min. Don't stir but carefully shake the pan instead to avoid breaking up the fish.
4
Add mussels, scamp and cherry tomatoes in the last 5min.
5
Serve the stew with soft polenta. Garnish with parsley.