Tuna cooked 46 C with Squid Ink Mayonnaise

I had a squid ink mayonnaise at Cercle restaurant and thought it could be a versatile sauce. Our grocery store sometimes has big thick tuna steaks so we got one, but wanted to cook it to barely done since there's no fat to keep it from drying out. I adopted the time, temp, and technique for tuna from Serious Eats, and the squid ink mayo from James Beard. Unlike 1990's seared raw tuna, this has a cooked texture that won't scare your auntie, but it's tender in a way that normal cooking cannot achieve. It was easy to put together and worked well enough we'd do it again.

Squid ink mayo under and over tuna, with endive

Tuna

       Salt

400 g  Tuna steak, 3-4 cm thick

 15 ml Olive Oil

Trim the skin off the tuna steak and dust generously with Salt, then put in a zip-top bag.

Let it hang out to dry cure for 30 minutes, then add the Olive oil.

Lower the bag in a sous vide bath set to 46C/115F and let the water pressure push out the air, then zip it shut; don't use a vacuum sealer as it will crush the fish and ooze out the oil.

Cook sous vide 45 minutes.

Squid Ink Mayo

Meanwhile, make the ink mayo. I get my squid ink form Bon Preu grocery store, it's 0.69€ for four little packets, and one is enough to flavor and color this.

  1   Egg Yolk

  4 g Squid Ink (1 packet)

      Juice of 1/2 Lemon

1/2 C Olive Oil

      Salt

Use an electric whisk to blitz the Egg Yolk, Squid Ink, then half of the Lemon Juice, saving some juice to adjust later.

With the whisk running, very slowly drizzle in the Olive Oil; it should emulsify into a classic mayonnaise consistency.

Taste and add Salt and more Lemon Juice if needed; I liked mine pretty bright so added all the juice.

Assembly

Dry the Tuna and get a plancha very hot, then film with oil; sear the Tuna for about 30 seconds per side -- you don't want to cook it any more.

Slice the tuna, it should be a cooked texture, but still a bit pink in the center.

Paint a plate with the Ink Mayo: I used a pastry brush but a fork might be more dramatic.

Fan the Tuna slices on the ink, dollop more on top as needed.

I served with pan braised endive. 

You can use any excess ink mayo on pasta, spread on bread/toast as a pintxo base, or a scary potato salad.

Next Time...

I'd cook the Tuna just a little lower to preserve more pink, maybe 45C.

My plancha didn't give a good sear, so I'd use carbon steel or cast iron.

A fork or squeeze bottle would probably make a more dramatic visual presentation.