Cusk au Gratin is a sophisticated yet homey dish that marries the delicate flavors of cusk, a type of white fish known for its flaky texture and mild taste, with a creamy, cheesy sauce, all under a golden, crispy topping. This dish is a testament to the versatility of seafood in the realm of gratins, a culinary technique often reserved for vegetables and pasta. By incorporating cusk, the recipe offers a lighter, yet equally indulgent, variation to the traditional gratin, making it a perfect meal for both casual family dinners and more formal gatherings.

The foundation of Cusk au Gratin is the cusk fillets themselves, seasoned simply with salt and ground black pepper. This minimal seasoning allows the inherent sweetness and freshness of the fish to shine, providing a clean base for the flavors that follow. The fish is laid out in a baking dish, ready to be enveloped in a rich sauce that transforms the simple fillets into a sumptuous feast.

What is cusk?

Cusk is a type of saltwater fish that belongs to the cod family and is primarily found in the North Atlantic Ocean. It is known for its firm, white flesh that offers a mild, slightly sweet flavor, making it a versatile ingredient in various culinary preparations. Cusk is often used in dishes where its flaky texture can be appreciated, such as stews and baked dishes like gratins. Due to its similarity to cod and haddock, cusk is a popular alternative in recipes calling for these more well-known fish.

The sauce, a velvety concoction of dairy and cheese, starts with a roux made from unsalted butter and all-purpose flour. This classic thickening agent is the backbone of many creamy sauces and ensures a smooth texture. To this, diced onions and minced garlic are added, both sautéed until softened and fragrant, infusing the roux with layers of flavor. Milk is gradually whisked in, creating a thick base that becomes the carrier for the grated Gruyère cheese. The Gruyère melts into the sauce, offering nutty and slightly sweet notes that complement the fish wonderfully.

The sauce is further enhanced with a teaspoon of Dijon mustard, adding depth and a hint of tanginess, while the juice and zest of a whole lemon lend a bright, citrusy accent that cuts through the richness of the dairy. A dash of paprika not only contributes a subtle warmth and complexity but also adds a hint of color to the sauce. Once complete, this creamy sauce is poured over the cusk fillets, ensuring each piece is generously coated.

The final component of Cusk au Gratin is the breadcrumb topping, a mixture of breadcrumbs, grated Parmesan cheese, and melted butter. This topping is evenly sprinkled over the sauced fish, creating a layer that will turn golden and crisp in the oven. As it bakes, the topping forms a delightful contrast to the tender fish and smooth sauce beneath, offering a textural variety that is pleasing to the palate.

Baked at 375°F (190°C) until the surface is bubbling and bronzed, Cusk au Gratin emerges from the oven as a cohesive dish where each element plays a crucial role. The fish remains moist and flaky, enveloped in a sauce that is creamy, cheesy, and subtly seasoned with mustard and lemon for balance. The crisp topping adds a necessary crunch, making each bite a harmonious blend of textures and flavors.

Garnishing with freshly chopped parsley and additional grated Parmesan cheese not only adds a burst of color and flavor but also introduces a fresh element to the dish, balancing the richness and tying all the components together. The parsley, with its light, herbal notes, and the Parmesan cheese, with its touch of umami, ensures that each serving is not only visually appealing but also a complete sensory experience.

Cusk au Gratin is a dish that resonates with comfort and sophistication. It showcases how a few quality ingredients, thoughtfully combined and cooked, can elevate a simple piece of fish into a meal that is both nourishing and indulgent. Served alongside steamed vegetables, a crisp salad, or crusty bread, it offers a satisfying dining experience that appeals to a wide range of tastes and occasions.

Cusk Au Gratin

5 from 1 vote

Recipe by Kyle Taylor Course: MainsCuisine: FrenchDifficulty: Easy

Servings

servings

Prep time

minutes

Cooking time

minutes

Total time

hour

Cusk au Gratin is a comforting baked dish featuring flaky cusk fillets enveloped in a creamy, cheese-infused sauce, topped with a golden, crispy breadcrumb and Parmesan crust.

Ingredients

For the Sauce:
2 pounds 2 cusk fillets
to taste, salt and ground black pepper
for garnish, freshly chopped parsley
for garnish, grated Parmesan cheese
For the Sauce:
2 tablespoons 2 unsalted butter
2 tablespoons 2 all-purpose flour
1 large 1 onion, diced
3 cloves of 3 garlic, minced
2 cups 2 milk
1 cup 1 Gruyère cheese, grated
1 teaspoon 1 Dijon mustard
1 whole 1 lemon, juiced and zested
1/2 teaspoon 1/2 paprika
to taste, salt and ground black pepper
For the Topping:
1/2 cup 1/2 breadcrumbs
1/2 cup 1/2 Parmesan cheese, grated
2 tablespoons 2 butter, melted

Directions

Preheat the Oven:
Set your oven to 375°F (190°C). Lightly grease a baking dish.
Prepare the Fish:
Season the cusk fillets with salt and pepper. Arrange them in the prepared baking dish.
Make the Sauce:
In a large saucepan, melt the unsalted butter over medium heat. Add the diced onion and cook until soft and translucent, about 5 minutes. Add the minced garlic and cook for another minute until fragrant. Stir in the flour to create a roux. Cook for 2 minutes, stirring constantly.

Gradually whisk in the milk, ensuring no lumps form. Bring the mixture to a simmer and cook until thickened, about 5 minutes. Remove from heat. Stir in the grated Gruyère cheese until melted and smooth. Add the Dijon mustard, lemon juice, lemon zest, and paprika. Season with salt and ground black pepper to taste.
Combine with Fish:
Pour the sauce evenly over the cusk fillets in the baking dish.
Prepare the Topping:
In a small bowl, mix together the breadcrumbs, grated Parmesan cheese, and melted butter. Sprinkle this mixture over the sauce-covered fish.
Bake:
Place the dish in the preheated oven and bake for 20-25 minutes, or until the topping is golden brown and the fish flakes easily with a fork.
Broil (Optional):
For an extra crispy topping, broil for an additional 2-3 minutes, watching carefully to avoid burning.
Serve:
Allow the gratin to cool slightly before serving. It pairs well with a variety of sides, such as steamed green vegetables, a fresh salad, or roasted potatoes.