Melt the butter in a large Dutch oven over medium-high heat. Add the onions, celery and a big pinch of salt. Cook, stirring occasionally, until the vegetables start softening, about 7 minutes. Add the chicken broth, 2 cups water, the clam juice, potatoes, bay leaves and 3/4 teaspoon salt. Make an X in the bottom of the chile pepper with a paring knife, exposing some of the seeds; add to the broth. Bring to a boil, then reduce to a steady simmer and cook until the potatoes are just tender, 13 to 15 minutes.
Season the fish with salt, add to the soup and simmer until starting to flake, about 5 minutes. Discard the chile pepper and bay leaves. Stir in the scallions. Divide the soup among bowls and top with parsley and pepper.
Photograph by Ryan Dausch
This recipe has been updated to more accurately recognize its origin or to add cultural context. It may differ from what was originally published or broadcast.