In a Dutch oven or heavy saucepan, cook the bacon until crisp. Remove with a slotted spoon and set aside, leaving about 2 tablespoons of bacon drippings in the pot.
Add the onion and celery. Cook 5–6 minutes until softened. Stir in the garlic and cook another 30 seconds.
Add the butter. Once melted, sprinkle in the flour and stir constantly for about one minute. You're not making a heavy roux—just enough to give the chowder a gentle body.
Gradually whisk in the chicken broth and all of the reserved clam juice until smooth.
Add the potatoes, bay leaf, thyme, and white pepper. Bring to a gentle simmer and cook about 12–15 minutes, or until the potatoes are just tender.
Stir in the half-and-half, heavy cream, Worcestershire, Dijon (if using), cooked bacon, and chopped clams.
Heat gently for about 5 minutes. Do not boil after adding the clams—they'll stay much more tender.
Remove the bay leaf. Stir in the parsley and taste for seasoning. Add salt only if needed, since the clams and bacon contribute plenty.
Serve with oyster crackers, crusty sourdough bread, or warm biscuits.