Ingredients:

  • 450 g (1 pound) Mixed Seafood (cod, haddock, prawns)
  • 1 medium Shallots, finely minced
  • 1 tbsp (15 g) Unsalted Butter (for sautéing)
  • 60 ml (1/4 cup) Dry White Wine (Optional)
  • 1 tsp fresh squeezed Lemon Juice
  • 1 tbsp Fresh Dill, finely chopped
  • Salt and Black Pepper, To taste
  • 55 g (4 tbsp) Unsalted Butter (for roux)
  • 55 g (4 tbsp) All-Purpose Flour
  • 600 ml (2 1/2 cups) Whole Milk, warmed slightly
  • 1 tsp Dijon Mustard
  • 1/4 tsp Freshly Grated Nutmeg
  • 60 g (2 ounces) Aged Cheddar or Gruyère Cheese, freshly grated (for sauce)
  • Salt and White Pepper, To taste (for sauce)
  • 50 g (1/2 cup) Panko Breadcrumbs
  • 30 g (1 ounce) Gruyère or Parmesan Cheese, grated (for topping)
  • 1 tbsp (15 g) Unsalted Butter, melted (for topping)
  • 1 tbsp Fresh Parsley, chopped (for garnish)

Instructions:

  1. Preheat oven to 200°C / 400°F (Gas Mark 6). Lightly butter your ovenproof gratin dish(es).
  2. In a small skillet, melt 1 tbsp butter. Sauté the minced shallots until softened and translucent (about 3 minutes). Set aside.
  3. Gently toss the raw, cubed seafood with the sautéed shallots, lemon juice, salt, pepper, and fresh dill. Spread this mixture evenly across the base of the prepared gratin dish.
  4. To make the roux: In a medium saucepan, melt the 55g butter over medium heat. Whisk in the flour constantly until a pale, smooth paste forms. Cook this paste for 1–2 minutes, stirring, until it smells slightly nutty.
  5. Gradually whisk the warmed milk into the roux, a splash at a time, ensuring each addition is fully incorporated and smooth before adding the next.
  6. Bring the sauce to a gentle simmer, whisking constantly. Once the sauce thickens enough to coat the back of a spoon (about 5–7 minutes), remove it from the heat.
  7. Finish the sauce: Stir in the white wine (if using), Dijon mustard, nutmeg, salt, white pepper, and 60g of grated cheese until the cheese is melted and the sauce is perfectly smooth and glossy. Taste and adjust seasoning.
  8. Pour the finished Béchamel sauce evenly over the seafood in the gratin dish. Ensure all the seafood is submerged.
  9. Prepare the topping: In a small bowl, combine the Panko breadcrumbs, the remaining grated Gruyère/Parmesan, and the 1 tbsp of melted butter. Toss well until the crumbs are evenly coated.
  10. Sprinkle the cheesy breadcrumb mixture evenly over the top of the sauce. Bake for 18–20 minutes, or until the sauce is bubbling around the edges and the topping is deeply golden brown and crisp.
  11. Remove from the oven and let the gratin rest for 5 minutes. Garnish with fresh parsley before serving.