Calm down. This dish of potato-wrapped halibut may look tricky, but it’s a lot easier than you think. But you’re going to need a mandoline – the kitchen kind – not the kind you use as musical accompaniment to “O Sole Mio.” The key to this dish is cutting the potatoes thinly enough – and it’s nearly impossible to do that without a mandoline. Even with the mandoline, the first time I tried this, I didn’t have the setting thin enough and the potatoes refused to hug the fish the way they were meant to. The ornery little slices were too thick and had minds of their own, and I ended up sticking toothpicks in them just to get them to stay put.
The second trick to this dish is to NOT soak the potato slices in water. You might be tempted to, thinking they won’t discolor that way. But what happens is that they’ll start to release some of their starch in the water – starch that they’ll need to stick to each other. And if you work quickly, the potato slices won’t discolor anyway.
Here’s how to make this simple dish. I’ve made it with halibut and with sea bass, but you could use any firm-fleshed white fish you like – cod also comes to mind. It needs to be fairly thick in size, so forget about flounder or sole or something equally thin and delicate. For two people, I used a piece of fish that weighed about 3/4 pound or so and one potato – scrubbed but unpeeled.
Take the skin off the fish – or have the fish monger do it for you before bringing it home. Sprinkle the fish pieces with salt, pepper and any herb you like. In this case, the herbs in the garden were still on their winter nap, so I used dried dill. Slice the potato very, very thinly with the mandoline.
Start to overlap slices over one of the pieces of fish – they’ll sort of remind you of fish scales.
Then flip it over and wrap the potato slices up and over the fish.
Cover any gaps with more potatoes and bring the slices up and over to meet and greet each other.
Press them gently together. If you have time, put the whole thing in the fridge for an hour. (I didn’t do this and had no problems, but if you’ve never made this dish, this step could make your life easier.)
Repeat the procedure with the other piece of fish and remaining potato slices.
Heat a cast-iron skillet and melt some butter inside. You won’t need very much butter if you have a seasoned skillet. You could use a nonstick skillet too, but I prefer the cast iron. Maybe you’ll use 2 T. butter at most for this entire thing. Use olive oil if you prefer. But not just plain old canola oil – you want the fat to impart some flavor and butter greases my wheel (or pan in this case) just right for this dish. Place the fish pieces gently into the skillet and adjust the flame or temperature of the burner if necessary. The temperature shouldn’t be so hot that the potatoes brown too quickly. You want the fish to cook through and if you brown the potatoes too quickly, then the fish will be raw in the middle. For this size of fish, the cooking time on each side was about three or four minutes. Let the slices brown before attempting to flip over. You want to flip these over only once - the less you handle the better your chances of keeping everything intact.
OK, flip over the fish – gently now – so you don’t mess up the nice pattern of potatoes. I also turned it over on the edges too, holding it between two spatulas, so those edges could cook and crisp up a little too. It’s a little hard to hold spatulas in both hands and take a photo too, so you’ll just have to imagine what that looks like. I know you can visualize.
I served it very simply with some lemon slices, but you could get fancier and make a sauce too. If you’ve got some aged balsamic vinegar, this would be a good time to crack it open and drizzle some on top.
But really, if you’ve got a good piece of buttery sea bass or halibut, all you need is a sprinkle of parsley and a squirt of lemon juice. Start to finish and you’re done in 30 minutes.