Crispy Fish and Plantain Gratin with Béchamel Sauce

Name: Crispy Fish and Plantain Gratin with Béchamel Sauce
Prep time: 60 min
Total time: 60 min
Yield: 10 servings
Cuisine: Française
Ingredients: 1 kg white fish fillets (cod, haddock or pollock); Juice of 1 lemon; 4 garlic cloves, minced; Salt and black pepper to taste; Neutral oil for frying; 200 g (1½ cups) all-purpose flour; 25 g (2 tbsp) butter; 700 ml (3 cups) whole milk; 1 yellow onion; 300 g mozzarella or mild melting cheese, thickly sliced; 3–4 plantains or firm bananas; Grated Parmesan to taste; Fresh flat-leaf parsley and chives, chopped

By Marie Lefebvre · Updated September 17, 2026

A comforting and exotic bake where golden crispy fish fillets meet a creamy homemade béchamel and caramelized plantain slices. This hearty, easy-to-make gratin brings bold and unique flavors to your dinner table — a real crowd-pleaser.

Prep⏱️ 60 min

Servings👥 10 servings

Difficulty📊 Easy

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🛒 Ingredients

10 servings

1 kg white fish fillets (cod, haddock or pollock)
Juice of 1 lemon
4 garlic cloves, minced
Salt and black pepper to taste
Neutral oil for frying
200 g (1½ cups) all-purpose flour
25 g (2 tbsp) butter
700 ml (3 cups) whole milk
1 yellow onion
300 g mozzarella or mild melting cheese, thickly sliced
3–4 plantains or firm bananas
Grated Parmesan to taste
Fresh flat-leaf parsley and chives, chopped

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Directions

1
Season fish fillets with salt, lemon juice and minced garlic. Let marinate for 20 minutes.
2
Make the béchamel: blend the onion, milk, butter and 60 g flour in a blender until completely smooth.
3
Pour into a saucepan and stir over medium heat until thickened. Season with salt, pepper and Parmesan. Set aside.
4
Heat oil in a large frying pan. Coat the fillets in flour, pressing firmly for a thick, even crust.
5
Fry the fillets in hot oil for 3–4 minutes per side until golden and crispy. Drain on paper towels and set aside.
6
Cut plantains lengthwise into thick slices. Pan-fry in a little oil until golden on both sides. Set aside.
7
Preheat oven to 200 °C (400 °F). Spread a thin layer of béchamel on the bottom of a baking dish.
8
Layer the fried fish fillets, followed by the cheese slices, then the golden plantains.
9
Pour the remaining béchamel over the top. Sprinkle generously with Parmesan and fresh herbs.
10
Bake for 15–20 minutes until bubbling and golden brown. Serve immediately.

💡 Chef's Tip

For an extra-crispy coating, add a teaspoon of smoked paprika or garlic powder to the flour. Plantains hold their shape much better during baking; if unavailable, use firm, slightly underripe bananas.