Heat EVOO, 3 turns of the pan, over medium-high heat in large pot or Dutch oven. Add fennel, onion, garlic, season with salt and pepper, and add in a bay leaf. Sauté 10 minutes.
Add vermouth or wine, stir, then add in saffron threads, stock and tomatoes. Bring to a boil, let reduce 5 minutes then add cod and seafood. Cover pot and cook 5 minutes, until shrimp are pink and firm, and fish is flaky and cooked through. Discard any un-opened mussels.
Serve in shallow bowls garnished with fennel fronds and basil with crusty bread alongside for mopping.