Sous Vide Flat Iron Steak: Easy and Delicious Top Blade!

Sliced Flat Iron Steak

Flat Iron Steaks are freaking amazing and rather hard to find.  This steak has several names and you might find these called a Butler’s Steak, an Oyster Steak or a Top Blade Steak.

Steak Label

This cut of beef is currently stuck in a beautiful little loop.  Because this steak is so hard to find most meat lovers don’t understand how awesome this cut is.   As a result, demand is low and the price is as well.  I can typically buy flat iron for about 40% less than a ribeye or New York strip.

Not only is this steak affordable but it is also one of the BEST steaks you can find.  Every few years the National Beef Board conducts studies on the quality of different cuts and grades of steak.  In these studies the flat iron is consistently rated as either the second or third most tender in the entire steer! (This study calls the steak a Top Blade Steak)

Let’s take a look at what this steak is, why it is so dang hard to find and how cook this beauty!

What is a Flat Iron Steak?

The flat iron is cut from the Chuck primal and is located just above the shoulder blade.  The muscle doesn’t really play a “load bearing” role but is more of a “support muscle” for the shoulder, something similar to a rotator cuff.

Because the steak comes out of the Chuck it is pretty cheap but since it only works to support the shoulder blade it remains a very tender cut.  This steak will typically weigh between 1 and 1.5 pounds and is usually very well marbled and is often mistaken for a flank steak.

Beef Cuts

The flat iron steak is difficult to retrieve from the Chuck and there is a large piece of tough gristle that has to be removed from the center of the steak.  Here is a great video that shows you exactly what it takes to get this steak from a steer.

Because the flat iron is such a hassle to harvest many butcher’s don’t bother with it and use it for ground chuck.  When butcher’s do harvest this steak they are left with two flat irons per Chuck.  Since there are two Chucks per steer there are only four flat irons per animal.

The percentage of butcher’s who will go through the trouble of harvesting this steak combined with the limited number of these steaks per animal is the reason why the flat iron can be so hard to find at your grocery store.

How to Cook a Flat Iron by Sous Vide

I am cooking almost all of my steaks with the sous vide method these days.  I started with a 1.5 pound steak with beautiful marbling. 

The three step cooking process for a perfect sous vide flat iron steak is to:

  • Season
  • Soak
  • Sear

Season the Flat Iron

My take on cooking this steak is to keep it simple and not over complicate things.  The meat is already incredibly tender and flavorful so I don’t bother with marinades, fancy dry rubs, etc.

The steak was seasoned on both sides with about a tablespoon each of salt and pepper.  If you wanted to add another flavor level then you could add a whole sprig of rosemary to the steak before it went into the bag.

Seal and Soak the Steak

The seasoned steak was sealed in a vacuum bag and simmered at 133.5F for two and a half hours.  I use the Anova immersion heater to maintain the water bath temperature and it does a great job.

Sous Vide Flat Iron Steak

You could cook the steak for up to four hours but I wouldn’t go much further than that as you don’t want this incredibly tender steak to turn to mush.

Sear the Steak

After the steak cooked for 2.5 hours I took the steak out of the bag and patted it dry with paper towels.

You will need to put a sear on your steak and can either use a cast iron skillet on your stove or you can fire up your grill. Whichever route you go you will want to get your cast iron or grill up to at least 500F for a proper sear.

I already had my Weber charcoal grill fired up to cook some side dishes so I used it and some GrillGrate panels to sear the steak for one minute per side.  

Grilled Flat Iron Steak

The process of starting with an incredibly tender steak and then cooking it in the gentlest manner possible results in a steak with a luxurious, velvety texture.

If you are a serious steak lover then this is a steak you have to make.  I could try to tell you how delicious this steak was but I would just come across as a drooling idiot.

It was awesome.

Sliced Flat Iron Steak

Sliced Flat Iron Steak

Sous Vide Flat Iron Steak

A Flat Iron Steak is cooked sous vide at 133F for 2.5 hours and then seared on a hot grill. This is an amazing and underappreciated cut of beef.
Prep Time 5 minutes
Cook Time 2 hours 30 minutes
Total Time 2 hours 35 minutes
Course Main Course
Cuisine American
Calories 300 kcal


  • 1 Flat Iron Steak 1-1.5 pounds
  • 1 tbsp kosher salt
  • 1 tbsp black pepper


  • Season the steak liberally with salt and pepper.
  • Seal the steak in a vacuum bag and immerse in a hot water bath maintained at 133F.
  • Simmer the steak for 2.5 hours.
  • Remove the steak from the water bath, take out of the vacuum bag and pat dry with paper towels.
  • Sear the steak at 500F in a cast iron skillet or on a hot grill for 1 minute per side.
  • Slice the steak thin and serve with sides of choice.
Keyword Sous Vide Flat Iron Steak