Creamy baked fish on potato gratin

This is a one-pan meal with fish baked in cream on top of a potato gratin with a golden crunchy topping. It’s a cross between a casserole, gratin and a pie. Fabulously cosy, rustic, oven baked fish recipe that’s effortless yet company worthy!

Creamy baked fish on potato gratin

This dish gives off very French-country vibes. Which, in hindsight, is rather unsurprising given it’s a recipe that our very own Chef JB just casually threw together one day. We ate it, loved it so much, declared it was “website-worthy” then proceeded to remake it…oh, I don’t know. Maybe 10, 12 times before we were fully happy with it and closed out all the “what ifs”?

Basically, it’s a creamy potato gratin, heavy on the leek (or onion), with fish that is baked on top at the same time, covered in a crunchy golden breadcrumb topping. So essentially, the breadcrumb topping acts as a lid, keeping everything steamy and succulent as the fish bubbles away in the creamy sauce while the gratin soaks up the tasty fish juices.

It’s just an all-out cosy dish of deliciousness!

Ingredients

Here’s what you need to make this:

Best fish

This recipe is best made with the more delicate white fish fillets that are around 2 cm (0.8″) thick. We don’t want fillets too thin else they will overcook. (UPDATE: Readers have made and loved it with salmon – read feedback in comments section!)

Our favourite fish to make this with is barramundi which is a popular Australian fish. Here are some more fish with similar cooking characteristics that will work great:

• barramundi (pictured), John Dory, snapper, basa, jewfish, blue eye cod (trevalla), tilapia, cod, halibut, pollock, hake, and salmon (readers have tried and loved – see recipe comments!).

Remember, the shape of fish means that you get thick cuts from the main body as well as thin cuts from towards the tail. Opt for the thicker cuts, aiming for 2cm/0.8″ thick. Pictured above is barramundi which is a thicker fish so we used the tail.

Skin on or off? Either is fine, it really won’t affect the bake time. But the skin won’t be crispy. If this is a turn-off for you, just eat the flesh and leave the skin.

Fish to avoid

I recommend avoiding:

• Fish that dry out easily when cooked – Like swordfish, tuna, bonito, kingfish, marlin, mackerel. Unless you’re extremely careful they can become dry inside so are very prone to overcooking in the oven. I feel these fish are (mostly) better in raw/rare form such as Ceviche, Poke Bowls, Tartare (also see Tuna Steak);

• Oily, “fishy” fish – Like mullet and sardines (try this recipe for sardines!).

For the potato gratin and creamy sauce

And here’s what you need for the rest of the dish:

• Potatoes – Floury (starchy) and all-rounder potatoes work best to achieve a lovely potato gratin flavour.
  – Australia: the cheap dirt-brushed potatoes sold everywhere (called Sebago) are ideal
  – US: Russet
  – UK: Maris Piper

• Leek – Flavour base for the gratin. Feel free to substitute with a standard onion!

• Garlic – Flavour base.

• Chardonnay or other dry white wine – This gives the sauce depth of flavour. Without, it tastes more one dimensional and like it’s missing “something”. Chardonnay is my favourite but any dry white wine that’s not too sweet or too woody will work fine. Non alcoholic substitute – More vegetable stock.

• Vegetable stock/broth – For semi braising the potatoes in a flavoured broth, tastier than using just water!

• Butter – For pan sautéing the potatoes before finishing them off in the oven.

• Panko, parmesan and olive oil – The crunchy topping!

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How to make Creamy Fish on Potato Gratin

This is a one pan meal that starts off on the stove and is finished in the oven. It would be handy if the whole dish could just be done in the oven, but we tried and the flavour was not as good. Whereas using the stove-to-oven method makes it company-worthy good!

1. Crunchy topping – Mix the panko and olive oil together, then stir through the parmesan.

2. Sauté the leeks and garlic, then cook the sliced potatoes for 6 minutes or until they are partially cooked. During this step, the potatoes absorb the flavour of the leek and garlic which is what makes the gratin so good!

3. Braise the potatoes firstly in wine for 1 minute (simmer rapidly to almost fully reduce to cook out the alcohol) then the vegetable stock for 1 1/2 minutes until reduced by half.

4. Top with fish pieces (which we first sprinkle with salt and pepper). Then pour over the cream, aiming for as much coverage as possible.

5. Topping – Sprinkle the entire surface with the crunchy topping.

6. Bake for 30 minutes – I PROMISE THE FISH DOES NOT OVERCOOK!! You would think it does, but it doesn’t. All that creamy goodness under the breadcrumb topping keeps everything moist and succulent!

   Broil/grill 4 minutes – Then to finish it off, I like to give it a quick 4 minute blast under the oven grill/broiler to give the topping lovely colour.

   Rest 5 minutes – Place on the counter and let it rest for 5 minutes before serving. Don’t skip this step! This is when the juices in the fish gets reabsorbed into the fibres so when you cut into the fish, it stays in the fish flesh (and ends up in your mouth) rather than running out onto the plate.

What to serve with Creamy Fish on Potato Gratin

All you need to finish off this meal is a fresh, crisp salad to serve on the side. Just toss leafy greens in French Dressing, or if you’re cooking for company, try the French Bistro Salad. On theme with the French-ish vibes going on in this dish!

I also wouldn’t say no to some crusty bread for mopping the plate clean. And for dessert – anyone for a pile of fresh baked Madeleines? Fast becoming a go-to for dinner parties because the batter is made in advance (you can even freeze it!) and stored in piping bags or jugs. Then it literally takes 2 minutes to pipe into the pan and 10 minutes to bake. How good is that!!! – Nagi x

Suggested sides

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Watch how to make it

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