Grouper Sous Vide with Vanilla and Lemon Zest

Sometimes I get the inspiration for a new dish from something I’ve enjoyed in a restaurant. Very seldomly I try to copy a dish exactly, but I do use the combinations of ingredients or preparations. At two Michelin star restaurant Don Alfonso 1890 near the Amalfi coast I had grouper that had been perfumed with vanilla and lemon zest, cooked sous vide, with a sabayon of anchovy brine, mashed potatoes, onion ashes, and fried basil. I didn’t think the onion ashes were very special and the fried basil seemed to be included mostly to have something green on the plate (which often makes a dish look better). The fish had been cooked sous vide at 55C/131F, and therefore it was just a tad dry. When I asked the chef about that, he said that the guests would not appreciate fish served medium rare (which I can imagine, because in Italy both meat and fish are served more done, such as well done tuna steak rather than rare). I especially liked the idea to perfume the fish with vanilla and lemon zest. The combination with the mashed potatoes and sabayon also worked very well. To include some vegetables (potatoes count as vegetables in Italy, but not in my book), I included some slow-roasted cauliflower. Anchovy brine (colatura di alici) is a specialty from the Amalfi coast that is not available here. Instead I’ve made an anchovy-flavored hollandaise sauce. At the restaurant the anchovy flavor wasn’t very prominent, which was the same in my version. So I suppose you could omit the anchovies altogether. I was happy with the result of this dish and will make it again.

Instead of grouper you could use any tender white fish that will not flake too much in the way that cod does. So halibut, wolffish, turbot, and sea bass are all good substitutes. I used halibut, because grouper is not easily available here.


Serves 4

  • 600 grams (1.3 lbs) grouper, halibut, turbot, or sea bass fillet
  • 500 grams (1.1 lbs) potatoes
  • 1 cauliflower
  • olive oil
  • salt and freshly ground white pepper
  • 75 grams (5 Tbsp) butter
  • 1 egg yolk
  • 120 ml (1/2 cup) dry white wine
  • 1 shallot, chopped
  • grated zest of 1 untreated lemon
  • 1 vanilla pod
  • 4 anchovy fillets, drained and chopped
  • 1 Tbsp minced fresh flat leaf parsley


Preheat the oven to 160C/325F (not fan forced). Break the cauliflower into florets, discarding the trunk, and place in a large oven dish or on a baking sheet. The cauliflower should be arranged in a single layer. Season with salt and drizzle with about 5 tablespoons of olive oil. Toss the cauliflower to cover it with the oil.

Roast the cauliflower in the oven at 160C/325F (not fan forced) for 2 to 3 hours, stirring every 30 minutes or so. If you can’t turn off the fan in your oven, use 150C/300F instead and stir every 15 minutes. The fan causes the cauliflower to cook unevenly and burn in spots.

The cauliflower is ready once it is nice and brown, but not black. It will shrink considerably, and the flavor will be nicely concentrated. People who do not usually enjoy cauliflower will often enjoy this rendition.

Divide the fish into 4 portions. Season the fish on both sides with salt (1 teaspoon of table salt for 600 grams of fish) and a little bit of freshly ground white pepper. Divide the grated zest of a lemon over both sides of each portion of fish. Halve the vanilla pod lengthwise, and scrape out the seeds with a small knife. Rub both sides of each portion of fish with a bit of the seeds. Reserve the empty pod for the sauce.

Vacuum seal the fish and allow the fish to dry brine in the refrigerator for at least 1 hour. This article explains why this is important.

The potatoes will retain more of their flavor if you cook them sous vide as well, but you could also just boil or steam the potatoes. Peel them, chop them into chunks of no more than than 3 cm (1 inch) thickness, vacuum seal in a single layer, and cook them sous vide for 90 to 120 minutes at 85C/185F.

If you own ‘only’ one sous vide appliance, you could cook the potatoes sous vide first and keep the mashed potatoes warm in a pot on the stove as described below, and then cook the fish sous vide. To do that, pour out part of the water at 85C/185F used for the potatoes (you could reserve this hot water for dipping the fish, see the advice at the end), and add cold water to bring it down to 50C/122F. Then set the sous vide to 50C/122F and put the fish in the water.

Place a chopped shallot in a saucepan with 120 ml of dry white wine, the empty vanilla pod, and 4 drained and chopped anchovy fillets.

Bring to a boil and then lower the heat to reduce gently…

…until only about 2 tablespoons of liquid (30 ml) is left.

Sift the liquid and return it to the saucepan. Press down with a spoon on the shallots in the sieve to get as much flavor out of them as possible.

It is a challenge with this dish to serve everything warm at the same time. So make sure to use preheated plates, by putting the plates in the oven with the cauliflower. (Porcelain plates are certainly resistent to 160C/325F of heat.)

When the potatoes are done, place them in a pot with a tablespoon of minced parsley, a generous glug of extra virgin olive oil, and salt to taste.

Mash the potatoes. If needed add some milk, water, or extra virgin olive oil.

The mashed potatoes should not be too soft and runny, but not too dry either. Keep the mashed potatoes hot on very low heat in a covered pot, stirring now and then to prevent the bottom from burning.

The fish only needs about 15 minutes of sous vide cooking at 50C/122F, assuming that the fillet is not thicker than 1.5 centimeters (1/2 inch). If it is thicker, look up the heating time in the table in this article.

Make the sauce at the end, while the fish is in the sous vide. This is because the sauce is prone to breaking if you allow it to get too hot.

Add 1 egg yolk and 75 grams diced butter to the saucepan with the liquid that you prepared earlier using white wine, shallot, anchovy, and empty vanilla beans.

Allow the butter to melt over low heat, stirring.

Keep stirring over low heat until the sauce has become thick, and then turn off the heat. If the heat is too high or you cook it for too long, the sauce will break.

It is best to do the plating of this dish with two people. One is making the sauce, while the other plates the mashed potato and cauliflower.

Take the fish out of the sous vide at the last moment (it is not a problem at all if the fish is kept in the sous vide for 5, 10 or even 15 minutes longer) and place it on top of the mashed potatoes. Pour some hot sauce on top of the fish. By placing the fish between the mashed potatoes and the sauce, it will keep its warmth better. Serve the dish as soon as possible, because it will still cool off rather quickly as the fish was cooked at 50C/122F.

A way to serve the fish at a higher temperature is to briefly dip the bag with the fish inside in nearly boiling water after sous vide cooking. Then take it out of the bag, and place it on top of the mashed potatoes.

Wine pairing

Because of the butter sauce and vanilla this is great with an oaked buttery white wine, such as an oaked Chardonnay (white Burgundy like Meursault). The best is an oaked white Bordeaux of Sauvignon Blanc and Sémillon, such as a Pessac-Léognan. The Sauvignon works well with the lemon zest, the oak with the vanilla, and the Sémillon with the butter.


6 thoughts on “Grouper Sous Vide with Vanilla and Lemon Zest

  1. So interesting as I am having ‘trouble’ combining vanilla in a savoury dish AND anchovy in a dish which obviously works ! Perchance because in my book anchovies always seem to come heads, tails and raw in a wonderful spicy marinade in a glass jar . . . . breakfast most days atop black bread !!!

    Liked by 1 person

  2. We sometimes had “Garupa” as the grouper is called here, for our bbq, and I have to admit that up to now, I’ve never thought about this fish being good when cut in fillets and prepared sous vide. But since we have many of them available around here, I’ll absolutely have to try it. 🤩👍

    Liked by 1 person

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