1 medium onion, chopped
1 green bell pepper, chopped
1 leek (white and pale green parts only), chopped
2 carrots, chopped
1 celery rib, chopped
1 medium tomato, peeled, seeded, and chopped
2 large garlic cloves, minced
3 tablespoons unsalted butter
3 cups fish stock or bottled clam juice
5 cups water
2 1/4 lb. mixed white fish fillets such as cod, grouper, tilefish, and snapper, skin and bones removed
1/4 cup tomato paste
1 bay leaf
1 teaspoon whole allspice, tied in a cheesecloth bag
1/2 teaspoon dried thyme, crumbled
1 teaspoon hot pepper sauce, or to taste
3 tablespoons cornstarch stirred together with 3 tablespoons water
12 small hard-shell clams such as littlenecks, scrubbed
1 lb. medium shrimp, shelled and deveined
2 to 3 tablespoons Worcestershire sauce
1/4 cup dark rum, or to taste
2 tablespoons Sherry pepper sauce
PREPARATION
Cook onion, bell pepper, leek, carrots, celery, chopped tomato, and garlic in butter in a 6-quart wide heavy pot over moderate heat, stirring frequently, until softened, about 10 minutes. Stir in stock and water and bring to a boil. Reduce heat and simmer briskly, uncovered, 20 minutes.
Stir in fish, tomato paste, bay leaf, cheesecloth bag of allspice, thyme, hot pepper sauce, and salt and pepper to taste. Simmer 20 minutes (fish will break up), then re stir cornstarch mixture and stir into chowder. Simmer, stirring occasionally, until thickened, about 2 minutes.
Stir in clams, shrimp, Worcestershire sauce, and rum and gently simmer 30 minutes. Remove from heat and let chowder stand, covered, 1 hour. Gently return to a simmer and stir in Sherry pepper sauce.