Heat a large pot over medium heat and add the chopped bacon. Cook until crispy, about 5 minutes.
Remove the bacon with a slotted spoon and set aside, leaving about 2 tablespoons of bacon grease in the pot.
Add the butter to the pot and melt over medium heat.
Stir in the diced onion and celery and cook for 3–4 minutes until softened.
Add the minced garlic and cook for 30 seconds until fragrant.
Sprinkle in the flour and stir constantly for 1 minute to create a roux.
Slowly pour in the chicken broth or reserved clam juice while stirring to prevent lumps.
Add the diced potatoes, salt, black pepper, and dried thyme.
Bring to a simmer and cook for 15 minutes, or until the potatoes are tender.
Stir in the chopped clams and heavy cream, mixing well.
Let the chowder warm through for 5 minutes without boiling.
Taste and adjust seasonings if needed.
Serve hot, garnished with the crispy bacon. Enjoy!