Preparing the Broth: In a large pot, bring the fish broth to a gentle simmer over medium heat.
Seasoning the Broth: Season the broth with salt, and if using, add black pepper. Adjust the seasoning according to your taste preferences.
Adding the Seafood: Add the mixed seafood to the simmering broth. Start with the items that take the longest to cook (like lobster tails and larger fish pieces), and end with those that cook quickly (like shrimp and scallops).
Simmering: Cook the seafood in the broth for 5-10 minutes, or until everything is just cooked through. Be careful not to overcook the seafood to ensure it remains tender.
Adding Cream: Reduce the heat to low and stir in the heavy cream. Warm the "bouillabaisse" through, but do not allow it to boil after adding the cream to prevent curdling.
Final Adjustments: Taste the "bouillabaisse" and adjust the seasoning if needed. The flavors should be rich and balanced, with the cream adding a luxurious texture to the broth.
Serving: Ladle the "bouillabaisse" into bowls, ensuring each serving includes a generous assortment of seafood.