Sous Vide Flat Iron Steak is an easy and foolproof recipe to cook this affordable cut, delivering intense beef flavor with very tender texture. Cooking it at a precise temperature in the sous vide water bath and finishing with a quick pan sear produce the best result.
What is flat iron steak?
Flat iron steak is considered to be very tender, second only to filet mignon in tenderness. It’s a cut coming from top blade which has a lot of flavorful marbling. It has the uniform thickness, and is less expensive than other tender beef cuts like rib eye or New York strip steak. Therefore, it’s also often used in fajitas and stir-fry dishes.
Benefits of sous vide flat iron steak:
Sous vide is a French cooking technique where the food is vacuum-sealed in a bag, and then cooked for a long time at a precise temperature in a warm water bath.
With traditional cooking methods like grilling, pan-searing, or broiling, there’s a very small window of the perfect doneness when making flat iron steaks. If you miss that window, the meat will become tough and chewy.
Sous vide cooking guarantees the result and ensures the steak is perfectly cooked by using precise temperature control. It also produces the meat with even doneness edge-to-edge.
How to cook sous vide flat iron steak
- Set the Sous Vide Precision Cooker to 135°F (57°C) for medium-rare doneness.
- Season the steak with salt, pepper, and garlic powder.
- Place the seasoned flat iron steak in a zip-lock bag and vacuum seal it using the “water displacement” technique. (You can use a vacuum sealer if you have one.)
- Place the bag in the sous vide water bath and cook for 2 hours.
- When the timer goes off, remove the bag from the water and transfer it to an ice bath or the refrigerator. Let it chill for about 10 minutes.
- Pat dry the flat iron steak with paper towels. Add more seasoning if needed. (It’s important to wipe off any extra moisture as it inhibits proper searing.)
- Then grill or sear for about 1 minute per side, just to caramelize the outside.
Flat iron steak seasoning / marinade
A simple seasoning made of salt, pepper and garlic powder can bring out the best natural flavor of the flat iron steak. Alternatively, flat iron steak is also a good candidate for a marinade as it’s relatively thin, and the flavor can penetrate into the meat easily.
Pro Tips: It’s important to season generously before sous vide cooking for the best result!
Sous vide flat iron temperature and time
I recommend cooking flat iron steak at 135°F (57°C) for medium-rare doneness. If you’d like to have a tender, juicy flat iron steak, don’t cook the meat past medium doneness. If you’d like to try other temperatures, follow the chart below:
|Medium Rare||135°F (57°C)|
|Well Done||165°F (73°C)|
Flat iron steak requires longer cook time than most other tender cuts, and I recommend cooking it for 2-4 hours.
Pro Tip: It’s fine to leave it in the warm bath for an extra 30-60 minutes. But avoid cooking it for too long as the texture could become mushy.
How to vacuum seal the steak without a vacuum sealer?
If you don’t have a vacuum sealer, a regular zip-top bag works well with this recipe. The trick is called water displacement technique: just place the seasoned steak in a zip-top bag, and seal all but one corner of the bag. Slowly place it into a bowl with cold water, making sure everything below the zip-line is covered by water. Then seal the rest of the bag (see the photo above).
Can I sous vide cook flat iron steak from frozen?
Yes! Follow the same instruction and cook the frozen steak 30 more minutes in the warm water bath.
Sides to pair with sous vide flat iron steak
More Sous Vide Steak Recipes
Sous Vide Flat Iron Steak
- 1 pound flat-iron steak
- 1/2 teaspoon kosher salt or to taste
- 1/4 teaspoon black pepper or to taste
- 1/4 garlic powder
- 1 tablespoon olive oil
- Add water to the sous vide container or a large pot, and set the Sous Vide Precision Cooker to (135°F/57°C) for medium-rare doneness. If you’d like to cook to other doneness, see the temperature chart in the post above.
- Season your flat iron steak generously with salt, pepper, and garlic powder.
- Place the seasoned steak to a zip-lock bag.
- Seal all but one corner of the bag, and slowly place it into a container with cold water. Make sure everything below the zip-line is covered by water, and push the air out. Then seal the rest of the bag. (This technique is called “water displacement method”).
- Place the vacuum-sealed bag into the sous vide water bath. Make sure it is fully submerged.
- Cook for 2 hours.
- When the timer goes off, remove the bag from the water bath and transfer it to an ice bath (or refrigerator). Let it chill for about 10 minutes.
- Remove the steak from the bag and wipe off the moisture with paper towels. (Make sure to pat dry the surface completely.)
- Season with more salt and pepper if necessary.
- Place the cast-iron skillet or grill on medium-high heat, and add olive oil. Once hot, add the steak and sear about 1 minute per side. (If you use grill, you can brush the oil on the steak).
- Slice against the grain and serve immediately.