Fry the bacon over high heat. Reduce heat and add the onion, celery and garlic and cook until onions are translucent. Remove mixture from heat and add to slow cooker. Except for heavy cream, add remaining ingredients, including salt and pepper to taste, to slow cooker.
Cook on low for four hours. Remove from heat, discard thyme sprig and bay leaves and stir in heavy cream.
Serve with warm bread and butter.