The Noble Ingredients of a Reinvented Fish Gratin

This cod gratin stands out for its bold combination: 400 grams of white fish meet a cheese duo consisting of 50 grams of Gruyère and 40 grams of grated Mimolette. This alliance creates a double texture, between the melting quality of the former and the bolder character of the latter, rarely exploited in traditional fish gratins.

The vegetable base structures the dish with 600 grams of potatoes, 2 leeks, and 200 grams of button mushrooms. These seasonal vegetables absorb the cod’s juices during cooking, transforming every bite into a concentration of marine and earthy flavors.

The originality lies in the seasoning: 2 teaspoons of mild curry flavor the béchamel, supported by 5 bay leaves infused in 75 centiliters of milk. This unexpected touch of spices awakens the natural sweetness of the cod without dominating it, creating an aromatic balance that avoids the blandness often associated with fish gratins.

The recipe suggests an alternative with Comté and nutmeg, proving that this gratin accepts cheese variations. For 4 people, these precise proportions guarantee a generous dish where noble proteins and vegetable accompaniment balance each other on every plate.

The Technique of Preparing Separate Elements

Before any assembly, each ingredient undergoes a specific treatment to guarantee uniform cooking. The potatoes, cut into one-centimeter thick slices, are plunged into boiling salted water for 10 minutes. This pre-cooking prevents them from remaining firm at the core during the 25 minutes in the oven, ensuring a homogeneous softness in the final gratin.

The cod requires meticulous inspection: every bone is removed with tweezers, a meticulous gesture that reveals the standard of this recipe. This operation, often neglected in quick preparations, guarantees a pleasant tasting experience. The fish is then cut into regular cubes, an essential calibration for perfect cooking alongside the vegetables.

The leeks are sliced into half-centimeter rounds, thinner than the potatoes to compensate for their shorter cooking time. The button mushrooms are finely sliced, thus releasing their water during simmering without excessively watering down the dish. This precision in cutting is not an aesthetic detail: it conditions the success of the next phase, where all elements will cook together in the flavored milk.

This segmented preparation, far from weighing down the process, allows for total control over the final texture of each component of the gratin.

Infused Simmering and the Cheese-Curry Béchamel

Once the elements are prepared, the fish, leeks, and mushrooms converge in a large saucepan with 75 centiliters of milk and five bay leaves. This 10-minute simmering over low heat transforms the milk into an aromatic broth, capturing the cod’s juices and the vegetable essence of the greens. This crucial step creates the flavor base for the entire preparation: an infused milk that carries the organoleptic memory of the fish.

Filtration through a sieve then separates the solids from the precious liquid. The simmered ingredients are placed in the gratin dish while the flavor-packed milk becomes the foundation of the béchamel. In a clean saucepan, 50 grams of butter melt before the sudden addition of 50 grams of flour. The roux is worked vigorously, then the flavored milk is gradually incorporated, requiring five minutes of monitoring over low heat and constant stirring.

Thickening requires patience and vigilance: the béchamel reaches its creamy texture when the wooden spoon leaves a persistent trail in the preparation. Only off the heat are the grated cheeses and mild curry integrated, avoiding any separation or lumps. This béchamel made with cod broth, enriched with the Gruyère-Mimolette duo and spiced with mild curry, constitutes the binder that will unify every layer of the gratin during its final cooking.

Layered Assembly and Oven Cooking

The construction of the gratin follows a precise logic. In the dish already containing the simmered fish-vegetable mixture, the first half of the cheesy béchamel is poured and gently incorporated with a fork. This lower layer, moist and generous, preserves the tenderness of the cod during cooking. The pre-cooked potato slices then completely cover this base, forming a thermal shield that regulates the heat.

The rest of the béchamel then uniformly coats the potatoes, creating a smooth surface intended to transform into a golden crust. This stratification is not arbitrary: it protects the fish from direct exposure to the oven’s heat while ensuring that the hardier tubers capture the thermal intensity necessary for browning.

Baking at 210°C for exactly 25 minutes marks the ultimate metamorphosis. The high temperature caramelizes the proteins and lipids on the surface, while the fan heat gradually penetrates the layers to harmonize the textures. The Gruyère and Mimolette melt into a blonde crust, their aromas intensify under the Maillard effect, and the curry diffuses its subtle warmth through the dish.

In total, 55 minutes separate the start of preparation from the removal from the oven. This recipe for four people transforms 400 grams of cod into a structured gratin where each element retains its integrity while participating in the overall balance. The volume of 75 centiliters of milk, converted into enriched béchamel, ensures creaminess without drowning the flavors or weighing down the whole.