Wash the clams several times in cold water. Make sure all of the clams are closed. Discard any clams that remain open after you tap on the shell. In a large pot over high heat, add 2 cups of water, the onion, celery, thyme, 1 bay leaf, and the peppercorns. Add the clams, cover and steam until all of the clams open.
Remove the clams from the liquid and remove them from the shells. Chop the clams into small pieces and set aside. Strain the juice through a fine strainer and reserve.
Cook the bacon in a heavy bottom pot over medium heat, until rendered and crispy. Add the onions, remaining 3 bay leaves, the thyme, crushed red pepper and butter. Cook until the onions are translucent. Add the potatoes and the reserved clam juice. Cook until potatoes are tender.
Add the heavy cream and chopped clams and simmer for approximately 5 minutes. Lightly season with salt and pepper, to taste, and stir in the chopped parsley.
Serve in bowls with oyster crackers.