Baked Salmon Gratin with Leek, Lemon, and Potato

Headnote

This dish is built on contrast: rich salmon, a clean potato base, and a restrained cheese crust sharpened by lemon and softened with sour cream. The leek is handled gently so it lends sweetness rather than weight. The result should be composed, moist, and precise, with a gratin top that is bronzed, not heavy.

Recipe essentials

Dish category: Baked fish dish
Cuisine or origin: European-inspired
Course type: Main course
Yield: 1 serving
Serving size: 430 g
Prep time: 15 minutes
Cook time: 25 minutes
Total time: 40 minutes
Difficulty: Moderate

Equipment

1 small saucepan
1 small sauté pan
1 ovenproof baking dish, 18 cm x 12 cm
1 mixing bowl
1 fine grater
1 knife and cutting board

Ingredients

Salmon, skinless: 180 g
Potato, peeled: 120 g
Leek, white and pale green only, finely sliced: 40 g
Sour cream: 35 g
Mayonnaise: 20 g
Egg: 25 g, lightly beaten
Cheese, finely grated: 25 g
Lemon, finely grated zest and juice: 10 g zest and 15 g juice
Butter: 15 g
Salt: 4 g
Black pepper: 1 g

Method

1. Heat the oven to 200°C. Lightly butter the baking dish with 5 g of the butter.

2. Place the potato in a saucepan, cover with cold salted water, and bring to a steady simmer. Cook for 12 to 15 minutes, until just tender at the center but still holding its shape. Drain well, cool briefly, then slice into 5 mm rounds.

3. Melt the remaining butter in a small sauté pan over medium heat. Add the leek and a pinch of salt, and cook for 4 to 5 minutes, stirring often, until soft, glossy, and sweet without browning. Remove from the heat.

4. In a bowl, combine the sour cream, mayonnaise, beaten egg, cheese, lemon zest, lemon juice, black pepper, and the remaining salt. Stir until smooth and evenly thickened.

5. Arrange the potato in the base of the baking dish in a neat overlapping layer. Spoon the leek evenly over the potato. Set the salmon on top in a single layer. Spoon the sour cream mixture over the salmon and spread it just to cover the surface.

6. Bake for 18 to 20 minutes, until the salmon is opaque at the edges and still moist in the center, the topping is set, and the surface is lightly bronzed. If needed, finish under a hot grill for 1 to 2 minutes to deepen the color without drying the fish.

7. Rest for 3 minutes before serving. The salmon should flake in clean layers, the potato should be tender, and the sauce should remain creamy rather than split.

Plating and serving

Lift the gratin onto a warm plate in one composed portion, keeping the layers intact. Spoon any creamy juices around the base, not over the top. Serve while the surface is still crisp and the interior remains supple.

Professional notes

Do not overcook the salmon; it should remain just opaque in the center. Drain the potato thoroughly so the gratin sets cleanly. The lemon must be present but restrained, giving lift rather than acidity.