Coastal French Gratin de Fruits de Mer with Gruyère Crust

🌍 Cuisine: French
🏷️ Category: Main Course
⏱️ Prep: 25 minutes
🍳 Cook: 30 minutes
👥 Serves: 4 servings

📝 About This Recipe

Transport your senses to the shores of Brittany with this luxurious seafood gratin, a timeless French classic that marries the ocean's bounty with a velvet-smooth Mornay sauce. This dish features succulent scallops, tender shrimp, and flaky white fish bathed in a delicate infusion of shallots and dry white wine. Topped with a golden, bubbling crust of nutty Gruyère and herbed breadcrumbs, it is an elegant masterpiece that celebrates the sophistication of pescatarian cuisine.

🥗 Ingredients

The Seafood Selection

  • 1/2 lb Large Shrimp (peeled, deveined, and tails removed)
  • 1/2 lb Bay Scallops (patted dry)
  • 1/2 lb Firm White Fish (Cod or Halibut) (cut into 1-inch chunks)
  • 1/2 cup Dry White Wine (Sauvignon Blanc) (for poaching)

The Velouté Sauce

  • 4 tablespoons Unsalted Butter
  • 1/4 cup All-Purpose Flour
  • 1.5 cups Whole Milk (warmed)
  • 1/4 cup Heavy Cream
  • 1 large Shallot (finely minced)
  • 2 cloves Garlic (pressed or minced)
  • 1/8 teaspoon Nutmeg (freshly grated)
  • 1 teaspoon Lemon Juice (freshly squeezed)

The Gratin Topping

  • 1 cup Gruyère Cheese (freshly grated)
  • 1/2 cup Panko Breadcrumbs
  • 2 tablespoons Fresh Parsley (finely chopped)
  • 1 tablespoon Melted Butter (for the topping)

👨‍🍳 Instructions

  1. 1

    Preheat your oven to 400°F (200°C). Lightly butter a 1.5-quart gratin dish or four individual ramekins.

  2. 2

    In a wide skillet, bring the white wine and 1/4 cup of water to a gentle simmer. Add the fish chunks, shrimp, and scallops in a single layer.

  3. 3

    Poach the seafood for just 2-3 minutes; it should be opaque but slightly undercooked in the center. Use a slotted spoon to transfer the seafood to the prepared baking dish, discarding the poaching liquid or saving it for a future stock.

  4. 4

    Wipe the skillet clean and melt 4 tablespoons of butter over medium heat. Add the minced shallots and cook for 2-3 minutes until soft and translucent.

  5. 5

    Stir in the garlic and cook for another 30 seconds until fragrant, being careful not to let it brown.

  6. 6

    Whisk in the flour to create a roux. Cook, stirring constantly, for 1-2 minutes to remove the raw flour taste.

  7. 7

    Slowly pour in the warmed milk a little at a time, whisking vigorously to prevent lumps. Continue cooking until the sauce thickens enough to coat the back of a spoon.

  8. 8

    Stir in the heavy cream, nutmeg, lemon juice, and a pinch of salt and white pepper. Taste and adjust seasoning as needed.

  9. 9

    Pour the creamy sauce evenly over the seafood in the baking dish, gently folding with a spoon to ensure every piece is coated.

  10. 10

    In a small bowl, toss together the Panko breadcrumbs, grated Gruyère, chopped parsley, and the tablespoon of melted butter.

  11. 11

    Sprinkle the breadcrumb mixture generously over the top of the seafood and sauce.

  12. 12

    Bake in the center of the oven for 15-20 minutes, or until the sauce is bubbling at the edges and the topping is a deep golden brown.

  13. 13

    For an extra crispy finish, turn on the broiler for the last 60 seconds, watching closely to prevent burning.

  14. 14

    Remove from the oven and let rest for 5 minutes before serving to allow the sauce to set slightly.

💡 Chef's Tips

Always pat your scallops and fish completely dry before poaching to prevent excess water from thinning your sauce. If you can't find Gruyère, Emmental or a high-quality sharp white cheddar make excellent substitutes for the crust. Avoid overcooking the seafood during the poaching phase; remember it will continue to cook in the oven. For a deeper flavor, use a pinch of piment d'Espelette or cayenne pepper in the sauce to provide a subtle warmth. Ensure your milk is warm before adding it to the roux to achieve the smoothest possible texture.

🍽️ Serving Suggestions

Serve with a crusty French baguette to soak up every drop of the decadent cream sauce. Pair with a crisp, chilled glass of Muscadet or Chablis to cut through the richness of the cheese. A simple side salad of bitter greens with a lemon-shallot vinaigrette provides a perfect acidic balance. Steamed asparagus or haricots verts tossed in lemon butter make a wonderful vegetable accompaniment. For a grander meal, serve over a bed of buttery saffron rice or angel hair pasta.