If your cod or shrimp are frozen, run them under cold running water for 15-20 minutes, or until thawed.
Meanwhile, dice the shallot and garlic, and measure out your spices for ease of use later.
Heat olive oil in a Dutch oven or large sauce pot over medium heat for 1-2 minutes. Add shallot, garlic, coriander and thyme sprigs. Sauté, stirring, for 2-3 minutes until shallots are translucent.
Add saffron and stir to combine for 1 minute. If needed, add additional olive oil to keep the combination from sticking to the Dutch oven.
Add chicken broth, clam juice/sauce, and diced tomatoes. Increase heat to medium high and bring to a boil. Reduce heat to medium low and let simmer, stirring occasionally, for 5 minutes.
Add drained beans, salt, pepper, lemon juice and hot sauce, if using. Let simmer, stirring occasionally, for 5 minutes.
Increase the heat to medium. Nestle the cod into the broth, ensuring that each fillet is fully covered by liquid. Cover and cook for 2 minutes without stirring.
Add shrimp, mussels and baby spinach, stirring as little as possible to keep the cod fillets intact. Add additional broth or water to ensure all of the seafood is immersed. Cover and cook 5 minutes until shrimp is pink, mussels have opened, and the cod is flakey.*
Taste broth and adjust with salt and pepper as needed. Removed thyme sprigs, if used. Serve with crusty bread and garnish with fresh thyme leaves, if desires.