We think the combination of shrimp and cod keeps things interesting, but you could easily make this soup with just one or the other; simply double the quantity of whichever you choose. Sautéing the croutons in oil keeps them from getting soggy in the soup. The clam juice here will not make the soup taste like clams, since the juice is diluted with water and juice from the tomatoes; it just punches up the fish flavor.
2 tablespoons butter
1 onion, chopped
2 ribs celery, chopped
2 cloves garlic, minced
1 teaspoon salt
1/2 cup dry white wine
1 1/4 teaspoons dried tarragon
1 cup bottled clam juice
1 2/3 cups canned diced tomatoes with their juice (one 15-ounce can)
3 cups water
2 cups 1/2-inch bread cubes cut from good-quality white bread
2 1/2 tablespoons olive oil
Fresh-ground black pepper
1/3 cup chopped fresh parsley
3/4 pound boneless, skinless cod fillet, cut into approximately 1-by-1/2-inch strips
3/4 pound medium shrimp, shelled and halved lengthwise
How to Make It
In a large pot, melt the butter over moderately low heat. Add the onion, celery, garlic, and 3/4 teaspoon of the salt. Cook, stirring occasionally, until the vegetables start to soften, about 10 minutes. Add the wine, tarragon, clam juice, tomatoes, and water. Bring to a boil. Reduce the heat and simmer for 10 minutes.
Meanwhile, put a medium frying pan over moderately low heat. Toss the bread cubes with the oil and the remaining 1/4 teaspoon salt; add them to the pan. Cook, stirring frequently, until crisp and golden brown, about 5 minutes. Remove from the heat and toss the croutons with 1/8 teaspoon pepper and 2 tablespoons of the parsley.
Stir the cod and shrimp into the soup. Cook, stirring occasionally, until the seafood is just done, 3 to 5 minutes. Stir in 1/4 teaspoon pepper and the remaining parsley and serve the soup topped with the croutons.
Wine Recommendation: Fish soup with an herb-infused broth makes us think of sunlit patios overlooking a shimmering Mediterranean. If you were in Nice, you'd be drinking a Provençal rosé. Why not here?