Italian Fish Stew recipes

Name: Italian Fish Stew recipes
Ingredients: 2 tablespoons extra virgin olive oil; 2 tablespoons butter; ½ cup leeks, white part cleaned of all sand and diced; 1 cup sweet onion diced, such as Vidalia; ½ cup fresh fennel bulb, diced (if fennel is not available, add one teaspoon crushed aniseed when sautéing onions and leeks); 1 tablespoon garlic, minced; ¼ cup Vermouth or dry white wine; 2 tablespoons tomato paste; 2 cups clam juice (2 8-ounce bottles); 1 ½ cups vegetable stock; 1 28-ounce can crushed tomatoes (We like Pastene San Marzano); 1 teaspoon kosher or sea salt; ½ teaspoon freshly ground black pepper; ¼ cup fresh Italian flat leaf parsley chopped; 6 tablespoons fresh basil, divided; Pinch red pepper flakes; ½ pound fresh zucchini quartered the long way then sliced into bite sized pieces; 1 cup fresh or frozen corn kernels; 1 pound firm white fish cut into large chunks (halibut, mahi-mahi, catfish, etc.)