In a large bowl combine 3 tbs olive oil, 2 tbs lemon juice, minced garlic, 1 tsp sea salt, 1 tsp black pepper, 1 tsp smoked paprika and 1 tsp red pepper flakes. Add the shrimp, scallops, fish chunks and calamari. Toss gently to coat. Cover and refrigerate for 15–20 minutes while you prepare other components. Do not over-marinate shellfish longer than 30 minutes.

Rinse mussels/clams under cold water, discard any with broken shells or that do not close when tapped. Pat all seafood dry with paper towels after marinating (reserve marinade).

Cook vegetables and deglaze

Heat 1 tbs olive oil and 2 tbs unsalted butter in a large, deep skillet or sauté pan over medium heat until butter foams. Add the chopped shallot and sliced fennel; cook, stirring, 4–5 minutes until softened and translucent but not browned.

Add halved cherry tomatoes and cook 2 minutes until they begin to wilt. Stir in the reserved marinade and lemon zest.

Pour in 120 ml white wine, increase heat to medium-high and simmer 2–3 minutes to reduce slightly and cook off alcohol.

Simmer seafood

Add 400 ml fish stock or clam juice and bring to a gentle simmer. Add mussels/clams first, cover and cook 3–4 minutes until they begin to open.

Add fish chunks, shrimp and scallops to the simmering broth, nestling pieces so they are submerged. Cover and simmer 3–4 minutes more until fish is opaque and flakes easily, shrimp are pink and scallops are opaque. Add calamari during the last 1–2 minutes so it remains tender. Discard any mussels/clams that do not open.

Finish and serve

Turn heat to low and swirl in 1 tbs cold cubed butter to mount the sauce, creating a glossy finish. Taste and adjust seasoning with additional salt or pepper as desired.

Sprinkle chopped parsley and torn basil leaves over the seafood. Scatter coarse sea salt if using and serve immediately with lemon wedges.

Serve the seafood and broth over crusty bread, steamed rice, or pasta if desired. Provide extra lemon wedges at the table.