Note: Adapted from Michael Cimarusti of Providence restaurant. Canned San Marzano tomatoes are available at most cooking and gourmet supply stores, as well as online.
3 3/4 pounds quahog or cherrystone clams
1 tablespoon (7.5 grams) extra-virgin olive oil
1 3/4 ounces (50 grams) salt pork
Scant 1 ounce (25 grams) pancetta, cut into ¼-inch dice
About 1 cup (87.5 grams) white onion, small dice
1/2 cup (50 grams) carrot, finely diced
1/4 cup plus 2 tablespoons (50 grams) celery, finely diced
1 small clove garlic, left whole and peeled
1 tablespoon (6.25 grams) jalapeño, finely diced
1 tablespoon (½ gram) crushed chile flakes
1 small branch each thyme, bay leaf, oregano, tied together into a bouquet
1/2 cup plus 1 tablespoon (125 grams) white wine
2 1/2 grams kosher salt, divided
1 cup (200 grams) San Marzano tomatoes in light purée
Clam broth, up to 1¾ cups (400 grams)
About 5½ ounces (150 grams) sliced small fingerling potatoes, such as Russian banana
1. Rinse the clams well under cold running water, scrubbing their shells with a brush.
2. Dry the clams a bit and place them in the freezer for one hour. This kills the clams and makes them much easier to open. Shuck the clams over a large container and reserve every drop of juice that drips from them. Coarsely chop the clams, and place them in a covered plastic container, separate from the clam juice. Refrigerate the clams until you are ready to finish the soup. Measure the clam juice; you will need 1¾ cups (make up for any shortage using canned clam broth).
3. Rinse the salt pork well under cold running water. Dice the salt pork into one-fourth-inch cubes. Rinse it again once it is diced for a minimum of 5 minutes. Drain well and set aside.
4. Heat the oil in a non-reactive saucepan over medium heat. Add the salt pork and pancetta and cook, stirring often, until they begin to render their fat, being careful not to brown. Add the diced onion, carrot, celery, garlic, jalapeño and chile flakes. Cook the vegetables, stirring often, until they are soft, translucent and aromatic. Add the bouquet and white wine, along with half of the salt. Bring the mixture to a boil and reduce by half.
5. Place the tomatoes and their juice in a mixing bowl, and crush them with your hands. Add the tomatoes, clam juice and sliced potatoes, and bring the soup to a simmer. Simmer until the potatoes are fully cooked. Remove the soup from heat. This makes about 1 quart of soup.Transfer the soup to a bowl set over a bowl of ice to stop the cooking and cool the soup quickly. Cover and refrigerate overnight.
6. Before serving, rewarm the soup: Bring the soup to a simmer and then add the chopped clams to keep them from getting over-cooked. Cook the clams for a minute or so while stirring. Check the seasoning and add the remaining salt if needed. Ladle the soup into warm bowls and garnish with a drizzle of olive oil and some tender yellow leaves of celery.