- 1 teaspoon vegetable oil
- 1 pound wild American shrimp, peeled, deveined, shells reserved
- 8 sprigs thyme
- 4 bay leaves
- 2 28-ounce cans whole peeled tomatoes with juices
- 1 pound slab bacon, cut into 1/2″ cubes, or thick-cut bacon, sliced into 1/2″ strips
- 4 celery stalks, finely chopped
- 3 carrots, finely chopped
- 2 onions, finely chopped
- 1 leek (white and pale-green parts only), finely chopped
- 3 garlic cloves, finely chopped
- 1/2 jalapeño (with seeds), finely chopped
- 1 pound new potatoes, peeled, cut into 1/2″ cubes
- Kosher salt, freshly ground pepper
- Hot pepper sauce (such as Cholula or Tabasco; optional)
- 1 pound black or striped bass fillet, cut into 1″-2″ pieces
- 1 pound black or red grouper fillet, cut into 1″-2″ pieces
- 6 slices baguette, toasted
- 6 cups cooked stone-ground grits or rice
- Chopped flat-leaf parsley
- Heat oil in a medium saucepan over medium heat. Add shrimp shells and cook, stirring constantly, until pink. Add 3 cups water and bring to a simmer. Cook gently until liquid is reduced to 2 cups. Strain stock, discarding shells. DO AHEAD: Can be made 1 day ahead. Cover and chill stock and shrimp separately.
- Tie thyme sprigs and bay leaves into a bundle with kitchen twine; set aside. Pulse tomatoes with juices in a food processor until chunky purée forms; set aside. Heat bacon in a large Dutch oven over medium-low heat; cook, stirring occasionally, until some of fat is rendered and bacon is just beginning to crisp, 10-15 minutes. Using a slotted spoon, transfer bacon to paper towels to drain; reserve 2 tablespoons bacon drippings for croutons.
- Add celery, carrots, onions, and leek to pot. Increase heat to medium and cook until vegetables are tender, about 10 minutes. Add garlic, jalapeño, and herb bundle; cook for 2 minutes. Add reserved tomato purée; cook, stirring often, for 20 minutes. Add shrimp stock (or, if omitting the first step, add 2 cups fish stock or clam juice) and bring to a simmer. Add potatoes and cooked bacon and simmer until potatoes are tender, about 15 minutes. Season stew with salt, pepper, and hot pepper sauce, if desired.
- Add fish and shrimp; bring to a gentle simmer. Cover; cook until fish and shrimp are just opaque in center, about 5 minutes.
- Meanwhile, brush bacon fat onto toast to make croutons. Ladle muddle into bowls over grits or rice, sprinkle with parsley, and garnish each bowl with a crouton.