Sous Vide Tuna with a Fennel Crust

There is not a lot to say about this except WOW! For any of you sous viders out there, this is an easy one with a low temperature and a short cook time. The fennel crust is simplicity itself. So, without faffing around, here’s the ingredients list.


My ingredients shots are used principally to remind me of what I used in the cooking. I served this with a nice soy mustard sauce. For the fish the ingredients are as follows;


  • 300gm piece of tuna loin
  • Rind of a lemon
  • A few sprigs of thyme
  • A teaspoon or two of olive oil
  • Salt and pepper to season
  • 2 teaspoons of fennel seeds

Side note on time and temperature. No matter what time and temperature I type into this recipe, it will attract comment from various sous vider types. Some saying I overcooked it, others saying I undercooked. I was happy. If you want to cook it less or more, knock yourself out, Though if you go too far under what I did, you might just do that. 

Slice nice big bits off the lemon (unwaxed) with a potato peeler (at least that’s what we call this device here in Ireland where we peel a lot of potatoes).

A peelin’ don’t you think?

Decorate both sides of the fish with the lemon rind and thyme sprigs.

Tuna, in the bag, decorated.

Pour in the olive oil before vacuum sealing the bag.

This oil has a particularly fine flavour and a delightful colour too.

Pop the sealed bag into your sous vide for an hour at 45ºC (113ºF). While that is going on, busy yourself dry frying the fennel seeds until they are aromatic and crunchy.

It really looks pretty before getting cooked.

The fish should come out looking something like this.

Lovely, delicate tuna steak.

Heat a cast iron pan to very hot and add a bit of oil. Remove the aromatics and season with the salt and pepper. Place it on the pan and sear on all sides. This will only take a couple of minutes. Avoid overcooking the fish.

I might have left it on a few seconds too long….

Sprinkle the fish with the fennel seeds, carve into nice slices and serve. It is beautiful with a simple sauce of english mustard powder mixed with soy sauce. Try it. It’s a really delightful dish.


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Latest comments
  • Brilliant use of sous vide, now all I need to do is get some tuna!

  • Hi Connor a lot of us don’t have a sous vide can this dish be cooked another way. Is a sous vide expensive ?

  • Simple but elegant. I wonder if I could achieve something vaguely similar without the sous vide machine by confiting the tuna in rather more olive oil than you’ve used. Or wait, a mix of olive and sesame…?

      • If confiting is a word, then confited definitely is, but on the other hand, if we’re going to go properly French about it, I suspect we should say confité and faire confir. I may have to pay a visit to the fisherman’s market once the lockdown is past; it’s 30kms away and therefore beyond the bounds of acceptable necessity.

  • The very moment I find a decent piece of tuna I am trying this…..

    thank you thank you thank YOU!

  • Lovely dish, Conor. Jody has a neglected sous vide apparatus sitting in one of her restaurants, so we be putting it to domestic use – this looks like a great idea. Nice pour shot. 🙂 Ken

  • You are the king of the pouring shots! I have a tree full of lemons and access to fresh thyme, so the next time I do a shopping run I’ll look for some tuna. It might be a while before I find some though, as the stores are still sort of picked over.

    Any cooking suggestions for those of us who haven’t joined the sous vide revolution yet? I was thinking of a 2-tiered process — a low pan or my crock pot on low to sort of heat it through and then a hot pan for the sear.

  • Looks incredible! I love that combo of tuna and fennel.

  • How very simple ! How very elegant ! To each their own: I do not think sous-vide will ever become one of my modes of cooking, but I just love the use of fennel seeds in your recipe and cannot wait to be able to try it . . . . keep on keeping well . . .

  • I would have bagged it first — the crock was just to try to mimic the sous vide, but now I’m afraid to mention the “c” word again. 😹

    We usually sear fresh tuna in a hot pan or cook it on the grill.

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