Clean the clams, rinse thoroughly, and soak in cold, lightly salted water for 2-3 hours without touching them, so that they open, releasing any possible remaining sand.
Chop the parsley. Pound 1 clove garlic in a mortar. Toast the bread. Take the clams out of the water and let them drain through your fingers (do not drain with a colander, to avoid picking up the sand as well). Crush the rest of the garlic and brown it with the olive oil in a large pan. When the garlic is lightly brown, remove with a pierced spoon and discard.
Add the tomatoes and a pinch of peperoncino. Cook for about 5 mins. and add the clams. Cover the pot and cook until all the clams are open. Add the chopped parsley and remove from fire. Place the bread into single bowls. Pour the broth with the clams over the bread and serve hot.
Note:
This zuppa can be prepared without tomatoes. Replace them with 1 cup of white wine; reduce for 2 mins. and add the clams. Proceed as above.
