Boil potatoes until just fork-tender.  Drain and reserve.

In a large saucepan, combine clam juice, onion, chicken bouillon granules, Worcestershire sauce, thyme, and pepper. Cover and simmer over medium-low heat until onions are tender, about 5 to 7 minutes.  Add potatoes to saucepan.  

Pour milk into medium mixing bowl. Add cornstarch and whisk until combined. Add to the saucepan.  Cook over medium-low heat, stirring constantly until slightly thickened, about 5 minutes.  Add clams and cook for another minute.  To serve, garnish each bowl of chowder with chopped parsley.