Step 1

In a large skillet, heat some cooking oil over medium heat. Sauté the onion and garlic until softened and fragrant, about 2-3 minutes.

Step 2

Add the fish fillet, baby squid, and prawns to the skillet. Cook until the seafood is just opaque and cooked through, about 3-4 minutes. Remove the seafood from the skillet and set aside.

Step 3

In the same skillet, melt the butter over medium heat. Sprinkle in the flour and cook, stirring constantly, until it forms into a roux, about 1-2 minutes.

Step 4

Slowly pour in the fish or seafood stock and white wine, stirring constantly to avoid lumps. Bring the mixture to a simmer and cook until slightly thickened, about 2-3 minutes.

Step 5

Reduce the heat to low and stir in the heavy cream and grated cheese. Continue to cook until the cheese has melted, and the sauce is smooth and creamy, about 2-3 minutes.

Step 6

Stir in the Dijon mustard and chopped parsley.

Step 7

Season the sauce with salt and pepper to taste.

Step 8

Return the cooked seafood to the skillet, gently folding it into the sauce until evenly coated.

Step 9

Transfer the seafood mixture to a large baking dish, spreading it out evenly.

Step 10

Sprinkle extra grated cheese on top if desired, top it with panko breadcrumbs for added texture. Place the baking dish in a 200C preheated oven and bake for 15 minutes, or until the top is golden and bubbly.

Step 11

Remove from the oven and let it cool for a few minutes before serving. Garnish with fresh parsley.

Step 12

Serve.