Sous Vide Flat Iron Steak

6 Min Read

This Sous Vide Flat Iron Steak is the perfect way to cook flat iron. It’s tender with a pink finish, coated in Creole seasoning, and seared in a cast iron for the easiest and most rewarding steak you’ve had in a long time!

Can a simple cut, like the flat iron, actually be a prime choice for entertaining? Turns out, yes!

With a very simple cooking method and a liberal coating of everyone’s favorite Creole seasoning blend, we take an affordable cut of steak and turn it into gourmet food.

This is the best flat iron I have ever hadGC Meat Labs Taste Tester

What is sous vide?

I get it. Sous vide sounds stupid fancy…and also complicated. But really sous vide cooking is just a bath of water heated to a low temp to cook steak perfectly and evenly. And hint, restaurants around the world use this technique simply because it produces consistent results.

It works amazingly on steaks, pork, chicken, and even fish! The best part is it takes a lot of the guesswork out of cooking by with simple science. By setting the temperature of the water bath, you are guaranteed to cook to the desired temp you are aiming for.

The water heats and circulates around the vacuum-sealed beef to cook it flawlessly to the temperature you program into the sous vide machine. The result is a pink edge-to-edge, evenly cooked slice of meat. Since we’re not applying an aggressive heat source, but gently cooking it with the heated water flowing around it to slowly raise the temperature, it becomes incredibly tender!

After the sous vide has run its course, then you quickly pan-sear the beef in cast iron to give it that crispy crust and it’s good to go! We do this because when beef comes out of the sous vide, altho it’s perfectly cooked, it doesn’t have that pretty crust we have come to love on our meat. It’s actually pretty darn basic!

What you’ll need to make this recipe:

You don’t need much to make this recipe!


  • Flat Iron Steak – you’ll need one 2-3 pound flat iron steak.
  • Marinade – use Tony Chachere’s Pourable Steakhouse Marinade.
  • Seasoning – use Tony Chachere’s Original Creole Seasoning, this
  • Butter – adds moisture and flavor depth.


In terms of the machine needed to actually do the sous vide method, you have a couple of options:

  1. Anova Circulator System (my favorite): This one can be attached to any size container, which means you aren’t limiting the size of the meat you’re working with.
  2. Sous Vide Machine: This is the entire package, countertop appliance. It’s easy to program and has the timers built-in. The only downside is it takes up precious real estate on a countertop.
  3. All-In-One Machine: A slow cooker that is also a rice cooker that is also a sous vide machine. I have the Wolf Gourmet one and it’s great.

Besides the actual circulation apparatus, you need a food-safe vacuum-sealed bag. You need to make sure the beef is vacuum-sealed because air pockets will cause the meat to float and it won’t cook evenly. A food saver is perfect for this because it comes with everything you need!

How to make sous vide flat iron steak

Marinate the steak: pour the marinade over the steak and let sit for 6-8 hours.

Prep the equipment: prep the sous vide machine according to manufacturers’ directions for 125ºF.

Prep the steak: pat the meat dry and rub with seasonings.

Sous vide process: place the steak into a food-safe sous vide bag and seal so there are no air pockets. Submerge the sealed steak into the water and set the timer for 1 hour. Once the flat iron has reached 125ºF, the sous vide is done.

Sear: take the steak and add it to a hot skillet with butter. Sprinkle on additional seasoning and sear on both sides until a crust forms.

What temperature do you sous vide steak at?

I prefer rare steak so I sous vide mine at 125ºF so once I sear it, it reaches 135ºF.

If you prefer a more well-done steak, adjust the temperature of the sous vide to reflect your desired temp minus 5-10 degrees. The final 5-10 will be achieved when you sear!

Can a sous vide steak get a good crust?

Totally! The sous vide method gives the meat an ultra tender texture but, once it’s done, you can sear it on the stove and still achieve that crispy crust we all want in a good piece of steak.

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