Potato and Salmon Gratin – Creamy, Comforting, Company-Worth

This Potato and Salmon Gratin layers thin-sliced potatoes with tender salmon, sautéed leeks, and a silky garlic-dill cream, all baked under a bubbling cheese top. It’s cozy enough for weeknights and elegant enough for guests.

You’ll see how to slice potatoes so they cook evenly, when to add the salmon so it stays moist, and the simple cream mixture that turns into a velvety sauce in the oven.

Why You’ll Love This Gratin

One pan, restaurant vibes – Slices like a casserole but tastes like a bistro dish.
Moist salmon – Added in generous pieces so it cooks gently inside the layers.
Silky sauce – Cream + stock + a touch of cheese = luscious without being heavy.
Make-ahead friendly – Assemble earlier; bake before serving.

Ingredients

For the gratin (9×13 inch / 23×33 cm):

2 tbsp butter or olive oil
1 medium leek (white & light green), thinly sliced (or 1 small onion)
2–3 cloves garlic, minced
2 lbs (900 g) waxy or all-purpose potatoes (Yukon Gold), peeled and thinly sliced (~2–3 mm)
1 lb (450 g) salmon fillet, skin removed, cut in 1-inch chunks
- Hot-smoked salmon also works; see variations.
1 cup (240 ml) heavy cream
1 cup (240 ml) low-sodium fish or chicken stock (or milk)
1 tsp Dijon mustard
Zest of 1/2 lemon + 1 tbsp juice
2 tbsp fresh dill, chopped (or 1 tsp dried)
1/2 tsp salt, plus more to taste
1/4 tsp black pepper
1 1/4 cups shredded cheese, divided (Gruyère, Swiss, or mozzarella)
Optional topping: 1/3 cup breadcrumbs mixed with 1 tbsp melted butter

For serving: extra dill, lemon wedges

How to Make Potato and Salmon Gratin

1) Sauté aromatics

Heat butter/oil in a skillet over medium. Add leek and a pinch of salt; cook 4–5 minutes until soft. Stir in garlic 30 seconds. Remove from heat.

2) Make the cream mixture

In a bowl or jug, whisk cream, stock, Dijon, lemon zest & juice, dill, salt, and pepper. Stir in 1/2 cup cheese.

3) Layer the gratin

Grease a 9×13 dish. Add half the potato slices (overlapping). Scatter half the leeks. Dot half the salmon pieces. Pour over half the cream mixture. Repeat layers with remaining potatoes, leeks, salmon, and cream.

4) Bake covered, then uncover

Cover tightly with foil. Bake at 375°F (190°C) for 35 minutes. Remove foil, sprinkle remaining 3/4 cup cheese (and buttered breadcrumbs if using). Bake 15–20 minutes more until potatoes are tender, top is golden, and edges bubble.

5) Rest, slice, serve

Let stand 10–15 minutes (sauce thickens). Sprinkle fresh dill and serve with lemon wedges.

Serving Suggestions

Crisp green salad with a sharp vinaigrette
Steamed green beans or roasted asparagus
Buttered peas with mint
Warm baguette for the creamy edges (highly recommended)

Cook’s Tips

Even slices = even bake. A mandoline makes this fast.
Season each layer lightly. Potatoes love salt—don’t be shy (but taste your stock).
Don’t overbake the salmon. The foil stage gently cooks it; the uncovered stage browns the top.
Rest before slicing. The sauce sets up and slices cleanly.

Variations & Add-Ins

Hot-smoked salmon: Swap for fresh; reduce salt slightly and skip lemon zest if your fish is very smoky.
Herb switch: Dill → chives, parsley, or tarragon.
Veg add-in: Layer in thin zucchini or spinach with the leeks.
Cheese twist: Use Parmesan on top for a sharper finish.

Storage & Reheating

Fridge: Cover and refrigerate up to 3 days.
Reheat: 325°F (165°C), covered, 15–20 minutes; uncover last 5 minutes to re-crisp.
Freezer: Best not to (potatoes can become mealy), but leftovers can be frozen tightly up to 1 month; reheat gently.

FAQ

Can I use canned salmon?
Yes—drain well, remove skin/bones, and fold into layers. Flavor will be a bit different but tasty.

Skin-on salmon okay?
Remove the skin for clean layers.

Can I make it ahead?
Assemble up to 6 hours ahead, cover, and refrigerate. Add 5–10 minutes to the first covered bake.

This Potato and Salmon Gratin is creamy, comforting, and quietly impressive. The potatoes turn tender in a dill-lemon cream while the salmon stays juicy under a golden, cheesy top. It’s a full meal in one dish—just add something green and call it perfect.