Seafood Casserole Recipe

Clean and portion shellfish

Rinse mussels and clams under cold water, discard any with broken shells or that do not close when tapped. Remove beards from mussels. Pat all shellfish dry. Cut cod into 1-inch pieces; pat dry. If shrimp are frozen, thaw, peel and devein; pat dry. Pat scallops dry and remove any side muscle.

Season cod, shrimp and scallops lightly with 1/2 tsp salt and 1/4 tsp black pepper. Set aside while you make the sauce.

Preheat oven to 400°F (200°C). Butter or grease a 9x13-inch (or similar) baking dish.

In a large skillet or sauté pan over medium heat, melt 2 tbsp butter with 1 tbsp olive oil. Add chopped onion and celery and cook until softened and translucent, about 6–8 minutes. Add minced garlic and cook 30–45 seconds until fragrant.

Sprinkle 3 tbsp flour over the softened vegetables and stir to make a roux. Cook 1–2 minutes, stirring, to remove raw flour taste but not brown it.

Deglaze the pan with 3 fl oz dry white wine, scraping any browned bits. Let the wine reduce by half, about 2 minutes.

Slowly whisk in 2 cups fish or chicken stock until smooth. Bring to a gentle simmer and cook 3–4 minutes to thicken slightly.

Reduce heat to low and stir in 1 cup heavy cream, 1 tsp Dijon mustard, 2 tbsp chopped parsley, 1 tbsp chopped dill or tarragon (if using), 2 tbsp lemon juice, remaining 1/2 tsp salt, 3/4 tsp black pepper and 1 tsp red pepper flakes. Taste and adjust seasoning. Keep sauce warm but not boiling.

Add parboiled baby potatoes (1 cup) and peas (1 cup) to the sauce and stir to combine so vegetables are evenly distributed.

Add cod, shrimp and scallops to the sauce and gently fold to coat. Arrange mussels and clams shell-side down so they sit evenly in the mixture. Spoon the mixture into the prepared baking dish, spacing seafood so shellfish have room to open during baking.

Pour any remaining sauce from the pan into the baking dish to ensure even coverage. Drizzle an extra 1 tbsp melted butter over the top for richness.

In a small bowl combine 1 cup panko breadcrumbs, 1 cup grated Parmesan, 3 tbsp melted butter and 1 tsp lemon zest. Mix until breadcrumbs are evenly coated.

Evenly sprinkle the breadcrumb mixture over the assembled seafood and sauce. Press lightly to adhere.

Bake in the preheated 400°F (200°C) oven for 18–22 minutes, until the topping is golden brown and the mussels and clams have opened. Check that shrimp are opaque and scallops are firm. If some shellfish remain closed after 22 minutes, discard them.

If you prefer a more browned top, switch oven to broil for 1–2 minutes watching closely to avoid burning.

Remove casserole from oven and let rest 5 minutes. Squeeze an additional 1 tbsp lemon juice over the top and sprinkle remaining 1 tbsp chopped parsley before serving.

Serve hot, spooning portions so each plate gets a mix of cod, shrimp, scallops, mussels, clams, potatoes and sauce. Provide lemon wedges on the side.