Sous Vide: Flat Iron Steak

The tenderness of the infraspinatus was discovered in the late 20th century. Prior to that it was just another piece of the primal chuck.


Serves: 2-3
Level of difficulty 2

Flat iron steak, 1 each. Typically, flat irons weigh just about 1 lb/.45 Kg.
White flour, 1 Tablespoon.
Egg whites, 1 each.
Kosher salt, 2 teaspoons.
Ground black pepper, a pinch.
Smoked Paprika, a pinch.
Vegetable oil, as needed.
Mushrooms, sliced, 3 oz/90 g.
Stovetop Demi-glace, 4 oz/100 ml. This requires approximately 3 hours to fabricate. There are numerous proprietary brands on the market that are perfectly adequate. Without endorsing, I think Knorr is the best value.
Parsley, as much as you can bear to endure chopping.
Red wine, 4 oz/100 ml.
Thyme sprigs, a few.
Carrots, 1 each, cut into strings using a mandolin or Swiss peeler.
Cherry tomatoes, 2 each, cut in half.
Kosher salt, as needed.
White vinegar, as needed.

Equipment requirements

Immersion circulator, portable or stationary.
Heat rated container, minimum of 2 gallons/8 liters.
Heat rated sous vide bags.
Channel or chamber vacuum device
12″/300 mm skillet.
Mandolin or Swiss peeler.

How do you like your flat iron?

The exact definition of “rare,” “medium rare,” “au point,” etc. is very subjective. A little practice will help you learn just exactly what temperature achieves your preferred appearance of doneness.

Here are some basic temperature setting guidelines used by restaurants:

Rare: 129 F/54 C.
Medium rare: 135 F/57 C
Medium: 140 F/60 C.
Medium well: 150 F/66 C.
Well done:  165 F/74 C.

Serves 2-3
Level of difficulty 2.25


Preheat the water in your sous vide bath to the temperature that most closely matches your preference. Most chefs try to arrive at an internal temperature of approximately 129 F/54 C. This is much easier to do using sous vide than by conventional methods.

Stage the flat iron into a dedicated vacuum bag. Seal and sous vide process at the temperature best suited to your preferences for a minimum of 4 hours. Because the rate of collagen conversion at sous vide temperatures is so low, the interval can be extended without any noticeable change in color or texture. AFTER the initial processing, lower the temperature to hold at 129 F/54 C for up to eight hours..

Finishing and Presentation:

Toss the carrot strings with a pinch of salt and pepper, add a few drops of oil and a few drops of white vinegar. Allow to cure for a few minutes and the carrots will soften.

Remove the flat iron from the bath, remove from the pouch and pat dry. Cut in half so that you have two approximate squares. Dust the steaks lightly with the flour. Smear the dusted steaks with the egg white–this will help the spices cling to the surface. Sprinkle with the salt, pepper, paprika, and a little chopped parsley. Store on a dry surface while you heat your pan.

Heat the skillet to a surface temperature of 275 F/135 C. Drizzle or spray one of the steaks with a few drops of vegetable oil. Add a few drops of oil to the pan as well and lay a steak in the pan. Brown for thirty seconds on each side, remove from pan and repeat the process with the other half of the steak. Remove from pan. There is now a butter sprayer on the market that I have been using one with good results. Coat or spray the steaks with a little butter, allow to rest for two minutes. Meanwhile,

saute the sliced mushrooms in the pan until they soften and darken. Add the wine to the pan, reduce to almost nothing, and add the demi-glace. Do not boil further.

Heat the plate in a 190 F/88 C oven–this is very important. Hot plates give you more time to create a deliberate presentation. Restaurants always use hot plates and one of the large chains takes great pride in advertising how hot their plates are–they usually arrive to the table sizzling.


Slice the steaks on the bias as thin as possible, as shown:

You can see the uniform appearance of doneness throughout the steak. Almost impossible to achieve by traditional means, this is one of many favorable features of the sous vide process. No matter how you like your steak, this principle applies. It is no longer necessary to “burn” a steak just to achieve a well done appearance–sous vide does that for you!


Set one of your plates on a flat surface. Arrange some mushrooms on the plate, drizzle with the sauce. Coil the carrots around the tines of a fork and lay on the plate as shown below. Crown with cherry tomatoes cut in half.

Arrange the sliced steak on top. I was trained to always shingle from right to left. I also sprinkle with parsley. Almost always.

As the steak imitates a roast, it can be served family style/banquet style–the flat iron is very lean and a little goes a long way.

Flat iron is one of my favorite steaks for sous vide application. It is just firm enough to benefit from the collagen converting properties of sous vide. After processing according to appropriate guidelines, it can also be shocked cold in ice water to 70 F/21 C and then kept at 40 F/4 C for an extended period of time. Sous vide processing pasteurizes the steak, like a carton of milk. This makes it convenient for an impromptu meal at any time of day–just treat as raw and sear as per the directions in this recipe until you achieve an internal temperature of approximately 125F, “mouth hot.”





Flat iron has a conveniently uniform shape and is easy to make the most of. There is no fat to be trimmed, even though the meat itself is usually pleasantly marbled. This lo-carb recipe utilizes the "London Broil" presentation, and can be served as an a la carte appetizer, entree, or even banquet type item. What you have is a moderately priced steak that you slice as if it was a more expensive roast!

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