1 pound Yukon Gold potatoes – peeled and 0.5-inch dice
2 cups whole milk
1 cup heavy cream
0.5 tsp black pepper – freshly ground
1 tsp kosher salt – or to taste
parsley – chopped (for serving)
oyster crackers – for serving
Instructions
Scrub the clams under cold running water, discarding any that are cracked. Set aside, 5 minutes.
Steam the clams with the water in a large pot over medium-high heat, covered, until most have just opened, 6–10 minutes; shake the pot once or twice. Transfer clams to a bowl to cool slightly; strain the steaming liquid through a fine-mesh sieve lined with a paper towel and reserve.
When cool enough to handle, remove clams from shells and coarsely chop; discard shells, 5 minutes.
In a Dutch oven, cook the salt pork over medium heat until the fat renders and the pieces turn golden and crisp, 6–8 minutes. Spoon out the cracklings and reserve for another use; leave about 2 tbsp fat in the pot, then add the butter to melt, 30 seconds.
Add the onion and celery and cook, stirring, until translucent and tender, 5–7 minutes. Stir in the thyme and bay leaf and cook until fragrant, 30 seconds (you will remove these before serving). Sprinkle in the flour and cook, stirring constantly, until foamy and no longer raw-smelling, 2 minutes.
Whisk in 3 cups total of clam liquid: combine all the reserved clam steaming liquid with enough bottled clam juice to reach 3 cups, whisking to avoid lumps. Bring to a simmer, then add the diced potatoes. Simmer gently until the potatoes are just tender, 10–12 minutes.
Stir in the milk and cream and return to a bare simmer (do not boil), 3–5 minutes. Add the chopped clams and any juices they released and warm through gently until just hot and tender, 1–2 minutes.
Season with the black pepper and kosher salt, adjusting to taste; the broth should be briny but balanced, 1–2 minutes. Remove the thyme sprigs and bay leaf. Let the chowder rest off heat to thicken slightly, 5 minutes.
Ladle into warm bowls, sprinkle with parsley, and serve with oyster crackers immediately.