Ingredients
Equipment
Method
- Preheat your oven to 375°F (190°C). If using frozen seafood, ensure it is fully thawed and patted dry to remove excess moisture. Cut any larger pieces of fish or scallops into uniform, bite-sized portions. If using shrimp, peel and devein them.
- Heat the olive oil in a large oven-safe skillet or in a separate saucepan over medium heat. Add the finely chopped onion and cook until softened and translucent, about 5–7 minutes. Add the minced garlic and cook for another minute until fragrant, being careful not to burn it. Transfer the onion and garlic mixture to a bowl and set aside.1 tbsp olive oil, 1 small yellow onion, 2 cloves garlic
- In the same skillet or saucepan, melt the 2 tablespoons of butter over medium heat. Once melted, whisk in the 2 tablespoons of all-purpose flour. Cook, stirring constantly, for about 1–2 minutes, until the mixture is pale golden and smells slightly nutty. This is your roux, which will thicken the sauce.2 tbsp unsalted butter, 2 tbsp all-purpose flour
- Gradually whisk in the milk, about half a cup at a time, ensuring each addition is incorporated before adding more. Continue whisking until the sauce is smooth and free of lumps. Bring the mixture to a gentle simmer, stirring frequently, and allow it to thicken for about 3–5 minutes.1.5 cups milk
- Stir in the heavy cream, dry white wine (if using), Dijon mustard, and freshly grated nutmeg. Season generously with salt and freshly ground black pepper to taste. Continue to simmer gently for another 2–3 minutes, allowing the flavors to meld. Taste and adjust seasoning if necessary; the sauce should be rich and creamy.1/2 cup heavy cream, 1/4 cup dry white wine, 1 tsp Dijon mustard, 1/4 tsp nutmeg, Salt and freshly ground black pepper
- Gently fold the prepared mixed seafood into the creamy sauce. Add the sautéed onion and garlic mixture back into the pan. Stir gently to ensure all the seafood is coated evenly with the sauce. If your skillet is not oven-safe, transfer the mixture to a greased 8x8 inch baking dish or a similar-sized gratin dish.1 lb mixed seafood (such as shrimp, scallops, crab meat, and/or fish fillets like cod or haddock), cut into bite-sized pieces, 1 small yellow onion, 2 cloves garlic
- Sprinkle the grated Gruyère cheese evenly over the seafood and sauce mixture. Top with the panko breadcrumbs, distributing them to create an even layer. This will create a wonderfully crisp and golden-brown crust.1/2 cup grated Gruyère cheese, 1/4 cup panko breadcrumbs
- Place the gratin dish in the preheated oven. Bake for 20–25 minutes, or until the sauce is bubbling around the edges and the topping is golden brown and crispy. The seafood should be cooked through and opaque.
- Once baked, carefully remove the Delicious Seafood Gratin Recipe from the oven. Let it rest for 5–10 minutes before serving. This allows the sauce to set slightly and makes it easier to serve.
Notes
This recipe can be refrigerated for up to 2-3 days. Reheat individual portions in the microwave or larger portions in a baking dish at 300°F (150°C) for 15-20 minutes. Freezing is also an option, though the seafood texture may change slightly upon thawing. Prepare as directed but do not bake. Freeze for up to 2-3 months. Bake from frozen at 375°F (190°C) for approximately 45-60 minutes, removing plastic wrap for the last 15-20 minutes to crisp the topping.