Heat the EVOO, three turns of the pan, over medium-high heat in large pot or Dutch oven. Add the fennel, onion and garlic, then season with salt and pepper and add in a bay leaf. Sauté for 10 minutes.
Add the vermouth or wine, stir, then add in the saffron threads, stock and tomatoes. Bring to a boil, reduce for 5 minutes, then add the cod and seafood. Cover the pot and cook for 5 minutes, until the shrimp are pink and firm and the fish is flaky and cooked through. Discard any unopened mussels.
Serve in shallow bowls garnished with fennel fronds and basil with crusty bread alongside for mopping.