Congrio is not available in the States, but you can substitute monkfish, red snapper, halibut, sea bass, grouper, tilefish, or a mixture.
3 tbsp. vegetable oil
1 large onion, halved and thinly sliced
1/4 red bell pepper, thinly sliced
1/2 carrot, grated
1 garlic clove, finely minced
1 1/2 tsp. sweet paprika
3 tomatoes, peeled, seeded, and coarsely chopped
4 cups fish stock, homemade or canned
3/4 cup dry white wine
1 bay leaf
4 sprigs parsley plus 1/2 cup minced parsley
Salt and freshly ground black pepper
4 fillets (2 inches thick) firm-fleshed white fish
1 lb. small mussels, clams, scallops, or shrimp (optional)
6 small potatoes, peeled and cooked (optional)
1 cup heavy cream
1 egg yolk
1. In a large saucepan, heat oil over medium heat. Add onion and sauté until softened but not browned, about 4 minutes. Add bell pepper, carrot, garlic, and paprika and cook, stirring occasionally, for 2 minutes.
2. Add tomatoes, broth, wine, bay leaf, and parsley sprigs. Season with salt and black pepper to taste. Bring to a boil, reduce to a simmer, and cook for 20 minutes.
3. Add fish, shellfish (if using), and potatoes (if using). Simmer over low heat until fish turns opaque and shellfish open, 10 to 15 minutes.
4. In a small bowl, whisk heavy cream with egg yolk. Gradually ladle some hot soup into the egg mixture before adding to soup. This prevents egg and cream from curdling. For the same reason, don´t let the soup boil. Sprinkle with fresh parsley before serving.