Once brown remove the bacon and about a ½ cup of the bacon fat. Keep the ½ cup of fat separate from the bacon lardons. Add in the onions, garlic and celery and sweat for 5 to 6 minutes.
Stir in the flour until combined to make a roux. Next pour in the sherry, clams, clam stock, chicken stock, and bay leaves and bring to a boil or until thick.
Once thick, add in the potatoes, thyme, cream, ½ of the cooked bacon, salt, and pepper and simmer over low heat for 15 to 20 minutes or until the potatoes are tender. Keep warm.