Preparation Heat oil in heavy 8- to 10-quart pot over medium heat. Add onions and garlic and sauté until onions are tender, about 10 minutes. Add tomatoes with juices and next 8 ingredients. Bring to boil. Reduce heat and simmer uncovered until flavors blend and liquid is slightly reduced, about 45 minutes. (Can be prepared 1 day ahead. Cool. Cover and refrigerate. Bring to simmer before continuing.) Add clams to cooking liquid. Cover pot and cook until clams open, about 10 minutes (discard any clams that do not open). Add cod, shrimp and scallops. Simmer until seafood is just cooked through, about 5 minutes. Season stew to taste with salt and pepper. Ladle stew into bowls. Sprinkle with basil and serve
Preparation Heat oil in heavy 8- to 10-quart pot over medium heat. Add onions and garlic and sauté until onions are tender, about 10 minutes. Add tomatoes with juices and next 8 ingredients. Bring to boil. Reduce heat and simmer uncovered until flavors blend and liquid is slightly reduced, about 45 minutes. (Can be prepared 1 day ahead. Cool. Cover and refrigerate. Bring to simmer before continuing.) Add clams to cooking liquid. Cover pot and cook until clams open, about 10 minutes (discard any clams that do not open). Add cod, shrimp and scallops. Simmer until seafood is just cooked through, about 5 minutes. Season stew to taste with salt and pepper. Ladle stew into bowls. Sprinkle with basil and serve