Portugese Clams in a Cataplana Casa Velha

Description
From my Aunt Maggie's collection. This one was marked a family favorite. Dated 1912.

Ingredients
Sauce:
 * 4 dozen uniformly small clams in the shell
 * 2 gallons cold water
 * 3 tablespoons salt
 * 2 tablespoons cornmeal
 * 3 medium Spanish onions, peeled and sliced thin
 * 3 large garlic cloves, peeled and minced
 * 2 large sweet green peppers, cored, seeded, and cut in thin strips
 * 1/4 cup olive oil
 * 1 large bay leaf, crumbled
 * 1 can (1 pound) water-pack tomatoes (do not drain)
 * 1 can (8 ounces) tomato sauce
 * 2 ounces lean prosciutto, cut into small dice
 * 1/4 pound lean smoked Ham, cut into small dice
 * 1/4 pound chouriço, chorizo or pepperoni, cut into small dice
 * 1/2 cup dry white wine
 * 1/4 cup coarsely chopped Italian parsley

Directions

 * 1) Scrub the clams well in cool water, pile in a large deep kettle, add the cold water, salt, and the cornmeal, which acts as an irritant that forces the clams to purge themselves of grit.
 * 2) Let the clams stand in the cold water about 1 hour. Meanwhile, prepare the sauce:
 * 3) Stir-fry the onions, garlic, and green peppers in the oil in a large heavy skillet over moderate heat 8 to 10 minutes until limp and golden.
 * 4) Add the bay leaf, tomatoes, and their juice. Break up any large clumps of tomatoes, bring mixture to a simmer, cover, and cook slowly for 30 minutes; add the tomato sauce, prosciutto, smoked Ham, and pepperoni, re-cover, and cook 30 minutes longer.
 * 5) Note: You can make the sauce as much as two days ahead of time but do not buy the clams until the day you plan to serve the cataplana.
 * 6) The sauce should be covered and refrigerated until you are ready to proceed.
 * 7) To assemble the cataplana, spoon half the tomato mixture into the bottom of a very large cataplana (it should measure about 15 inches across) or into a large heavy Dutch-oven type of kettle, and bring to a simmer over moderate heat. Adjust the heat so that the mixture barely boils, arrange the clams on top, spoon in the remaining tomato sauce, cover tight, and cook 10 minutes over moderately low heat.
 * 8) Open the cataplana or kettle, pour in the wine, scatter the parsley evenly on top, then toss the clams lightly. #Re-cover and cook slowly 15 to 20 minutes longer until the clams open — discard any that do not.
 * 9) Carry the cataplana or kettle to the table, open, and ladle into large soup plates.