In a large pot, braise bacon; add butter, onions and garlic.
Add peppers, celery and chopped clams. Cook together 5 minutes on medium heat (stirring continuously).
Add clam juice, bay leaves, salt & pepper to taste. Reduce for 10 minutes; add heavy cream, reduce for 10 more minutes.
Add potatoes and cayenne; reduce 10 more minutes.
Dissolve ¼ cup cornstarch in water and add to soup; let thicken.
Let soup rest with heat off for 15 minutes before serving.