Cook bacon – In a large pot, cook bacon until crispy. Remove and set aside, leaving 2 tablespoons of drippings in the pot.
Sauté vegetables – Add butter, onion, celery, carrots, and garlic to the pot. Cook 5 minutes until softened.
Build the base – Stir in potatoes, reserved clam juice, clam broth, chicken broth, thyme, bay leaves, salt, and pepper. Bring to a boil, then reduce to simmer 20 minutes until potatoes are tender.
Make it creamy – In a small bowl, whisk flour into cream. Slowly stir into soup, simmering 5–7 minutes until thickened.
Add clams – Stir in chopped clams and half of the bacon. Cook another 2 minutes (don’t overcook clams).
Serve – Ladle into bowls, top with extra bacon and parsley, and serve hot with oyster crackers or crusty bread.