Clam Chowder with stalks

3 potatoes , peeled and chopped 1 onion , chopped 2 carrots , chopped 2 stalks celery , chopped 7 cups chicken broth 1 bay leaf cayenne pepper 6 1/2 ounces[...]

12 tablespoons unsalted butter , divided 2 cups yellow onions , chopped (2 onions) 2 cups celery , medium-diced (4 stalks) 2 cups carrots , medium-diced (6[...]