In a large Dutch oven, cook the diced salt pork over medium-low heat for 8-10 minutes until the fat has rendered and the pork is crispy. Remove the crispy bits with a slotted spoon and set aside. Leave about 2 tablespoons of fat in the pot.

Add the butter to the pot. Once melted, add the onion and celery and sauté for 6-8 minutes until soft and translucent, but not browned.

Sprinkle the flour over the vegetables and cook, stirring constantly, for 2 minutes to cook out the raw flour taste.

Slowly whisk in the bottled clam juice and the reserved juice from the canned clams until smooth. Add the diced potatoes, thyme sprigs, and bay leaf.

Bring to a simmer, then reduce heat to low, cover, and cook for 10-15 minutes until the potatoes are fork-tender.

Remove the thyme sprigs and bay leaf. Reduce heat to the lowest setting. Stir in the heavy cream and whole milk. Heat through gently for 5 minutes without boiling.

Stir in the drained, chopped clams and cook for 1 more minute just to heat them through.

Remove from heat. Season to taste with kosher salt and black pepper. Ladle into bowls and garnish with the reserved crispy salt pork and fresh chives.