1 1/2 teaspoons kosher salt, plus more for seasoning fish
Freshly ground black pepper
1 1/2 pounds firm white fish fillets, such as halibut, snapper, grouper, or cod
1 pound shrimp, peeled and deveined
1 tablespoon chopped fresh parsley leaves
Garlic-Rubbed Croutons, for serving, recipe follows
In a 6 quart saucepan or soup pot, heat the oil over low heat. Add the onion, celery, and garlic and cook until tender, 6 to 8 minutes. Add the white wine, tomato paste, saffron, stock, crushed red pepper, orange juice, and orange zest and bring to a simmer. Cook uncovered, for about 45 minutes, or until liquid is reduced by about one-third.
Add the fennel and tomatoes and cook until the fennel is tender, about 20 minutes. Season with salt and freshly ground black pepper, to taste.
Season the fish fillets with salt and freshly ground black pepper. Cut the fillets into 1 1/2-inch chunks. Add the fish, shrimp, and parsley to the broth and allow to cook, gently stirring only once or twice, until the fish is cooked through, about 5 minutes. Serve in shallow bowls with garlic-rubbed croutons.
Place the French bread slices on a small baking sheet and brush with the olive oil. Bake until golden brown and crispy, about 10 minutes. While still warm, rub each crouton with one of the cut sides of garlic.