Saute the fatback in a nonreactive stockpot over medium heat for 5 minutes. Add the onion and saute until tender, about 10 minutes.
Add the clams, cover the pot and steam until the clams open, 7 minutes. Remove the clams, discard the shells, and set the clam meat aside. Discard any that do not open.
Add the potatoes, tomatoes, wine and 3 cups water to the stockpot. Bring to a boil, then reduce the heat and simmer for 5 minutes. Stir in the thyme, parsley, black pepper and creacker crumbs and simmer for 5 minutes. Add the clams and simmer for 3 more minutes. Whisk in the butter; adjust the seasonings.
Serve: HOT! SOURCE: NEW YORK COOKBOOK, by Molly O'Neill; WORKMAN PUBLISHING COMPANY; NEW YORK, NY; 1992; IBSN 1-556305-337-3