3 1/2 pounds skinless, boneless fish

1/4 pound meaty salt pork, cut into 1/4- to 1/2-inch dice

4 tablespoons unsalted butter

2 large onions, cut into 3/4-inch dice

3 bay leaves

1 tablespoon chopped fresh thyme

3 or 4 large Maine or other boiling potatoes, peeled and halved lengthwise, then cut into 1/4-inch slices

3 cups strong fish stock or 2 cups bottled clam juice diluted with 1 cup cold water

2 cups heavy cream

Salt and freshly ground black pepper, to taste

2 tablespoons chopped fresh parsley

2 tablespoons chopped fresh chervil (optional)

8 tablespoons (1 stick) unsalted butter

Leave the fish in as large pieces as possible, since it tends to flake when the chowder is stirred.

In a large flameproof casserole, render the salt pork until it begins to turn crisp. Add the 4 tablespoons of butter with the onions, bay leaves and thyme.

Cook the mixture for 5 minutes or until the onions are soft but not brown. Add potatoes and fish stock or diluted clam juice, and bring the mixture to a boil. Lower the heat and simmer the potatoes for 20 minutes or until they are tender.

Remove the bay leaves from the stock. Add the fish and heavy cream. Bring the soup to a boil, lower the heat, and simmer for 8 to 10 minutes or until fish is cooked through and beginning to flake. Add salt and pepper, stir in the parsley and chervil, if using, and remove the soup from the heat.

With a slotted spoon, transfer the chunks of fish, onions and potatoes to soup plates. Ladle the piping broth into the bowls. Add a tablespoon of butter to each soup plate and serve with crackers or biscuits.

Serves 8.