
This creamy salmon potato gratin layers tender potatoes, flaky salmon, and sweet fennel in a light white sauce. Baked until bubbling and topped with crisp breadcrumbs, it makes an elegant but comforting seafood dinner for any night of the week.
Preheat the oven to 425°F (220°C). Gather and measure all ingredients. Thinly slice the fennel bulb and onion, reserving a few fennel fronds for garnish if desired.

Scrub the potatoes and slice them into thin rounds. If the skins are tender, leave them on. Sprinkle lightly with salt, cover with a damp paper towel, and microwave for about 7 minutes, or until just starting to soften.

Cut the salmon into bite-size pieces. Toss with the white wine and a pinch of white pepper, then set aside while you prepare the sauce.

Melt the butter in a frying pan over medium heat. Add the onion and sliced fennel, season with a little salt, and cook for 5 to 6 minutes until softened but not browned.

Sprinkle the flour over the vegetables and stir well for 1 to 2 minutes over low heat so the flour cooks through and no dry patches remain.

Gradually pour in the milk, stirring constantly to prevent lumps. Simmer gently until the sauce thickens to a creamy consistency, then season with salt and white pepper to taste.

Heat a little olive oil in a separate pan. Lightly sear the salmon for 1 to 2 minutes, just until the surface turns opaque. Remove, then quickly saute the potato slices in the same pan for a few minutes to add color.

Arrange the potatoes and salmon in an oven-safe baking dish, layering them evenly. Spoon the fennel cream sauce over the top and spread it to cover.

Sprinkle with panko breadcrumbs and drizzle lightly with olive oil. Bake for 15 minutes, or until the top is golden and the gratin is bubbling around the edges. Rest for 5 minutes before serving.

If fennel is unavailable, use a small leek or extra onion for a milder flavor. Do not fully cook the salmon before baking or it may turn dry in the oven. Leftovers can be refrigerated in an airtight container for up to 2 days and reheated in the oven for the best texture.