Heat the oil in a very large pot over medium heat. Add the fennel, onion, shallots, and salt. Saute until transluscent, about 10 minutes.
Stir in tomato paste and cook for 1 minute.
Add wine, deglaze the pan and cook for 1 minute.
add tomatoes with their juices, fish stock, clam juice, and bay lead. Cover and bring to a simmer. Reduce heat to medium-low. Cover and simmer until the flavours blend, about 30-45 minutes.
Open the lid, raise the heat, and reduce by 25-30% (the shellfish will add a lot of liquid).
Season the fish and the shrimp with salt & pepper.
Optional: sear the fish on both sides, quickly (1 min) in hot olive oil to prevent it from falling apart once added to the pot.
Season the soup to taste with more salt and red pepper flakes if needed.
Add the frozen clams and mussels. Add the thawed shrimp, calamari, fish, and any other seafood. Simmer gently until the fish and shrimp are just cooked through and the clams and mussels are warm (3-5 minutes). Be mindful to not stir too much or the fish will break apart.
Toast thick slices of bread with butter (and garlic if you like). Season with salt & pepper.
Ladle the Cioppino into bowls, sprinkle chopped parsley and serve with toasted bread.
