8 pounds cherrystone clams, scrubbed
1 tbsp unsalted butter
8 ounces bacon, cut into 1/2-inch pieces
2 celery stalks, minced
1 large onion, minced
1 garlic clove, minced
2 1/2 pounds Yukon Gold potatoes, peeled, cut into 1/2-inch pieces
1 tablespoon chopped fresh thyme
1 bay leaf
2 tablespoons cornstarch
2 cups heavy cream
Kosher salt, freshly ground pepper
Chopped fresh chives
Oyster crackers or Vermont Common Crackers
Bring clams and 4 cups water to a boil in a large pot over high heat. Cook until clams just open, 8-10 minutes (discard any that do not open). Using a large slotted spoon, transfer clams to a large rimmed baking sheet; set broth aside. Let clams cool slightly, then pull meat from shells; discard shells.
Chop clams into bite-size pieces. Strain broth through a fine-mesh sieve set over a large bowl. Add water if needed to measure 6 cups. DO AHEAD: Clams and broth can be made 1 day ahead. Cover separately and chill.
Melt butter in a large heavy pot over medium heat. Add bacon and cook, stirring occasionally, until fat is rendered and bacon begins to brown, about 8 minutes.
Add celery, onion, and garlic and cook, stirring often, until onion is translucent, about 10 minutes.
Add reserved broth (or 6 cups bottled clam juice), potatoes, thyme, and bay leaf.
Bring chowder base to a simmer; cook until potatoes are tender, 20-25 minutes.
Stir cornstarch and 2 tablespoons water in a small bowl to form a slurry. Stir slurry into chowder base; return to a boil to thicken. DO AHEAD: Base can be made 1 day ahead. Let cool; cover and chill. Keep clams chilled. Bring base to a simmer before continuing.
Remove base from heat. Discard bay leaf. Stir in reserved clams (or two 10-ounce cans baby clams) and cream. Season with salt, if needed (clams’ brininess varies), and pepper.
Divide chowder among bowls. Garnish with chives and oyster crackers.
From Bon Appetit