This easy Sous Vide Flat Iron Steak is incredible because it delivers a perfectly cooked, juicy, and flavorful steak with minimal effort! This easy, foolproof cooking method is great for any steak lover, whether it’s an everyday dinner or a special occasion. Most of the cooking time is hands-off, and the sous vide does all the work for you. You can spend the time preparing the side dishes or simply relaxing until dinner is ready.

Sliced sous vide flat iron steak on a cutting board.

Flat iron steak is a mouth-watering cut of beef that’s known for its rich, robust flavor and tender texture. The best part? It’s one of the more inexpensive cuts of beef. So, for all you steak lovers out there being mindful of the pennies, this is an excellent option. It delivers that high-end taste, like a ribeye or filet mignon, without breaking the bank.

The Best Way to Enjoy Flat Iron Steak

If you’re new to sous vide cooking, I’m here to tell you it’s the perfect way to enjoy flat iron steak. It ensures even doneness, as it has no overcooked or undercooked spots, and remains incredibly juicy and tender. Traditional cooking methods like only grilling or pan-searing can sometimes result in accidental overcooking, leading to a tough and dry steak, and no one wants that! To get the perfect steak every time, this is a method I highly recommend. Also, this sous vide flat iron steak pairs perfectly with decadent truffle mashed potatoes, roasted asparagus, or honey sriracha brussel sprouts.

Ingredients for sous vide flat iron steak: platter with steak, dish of seasoning rub and sprigs of fresh thyme.

Why This Steak Recipe Works

Flat iron steak sous vide style is easy to prepare with simple ingredients.
Enhanced flavor: preparing the steak sealed with its own juices and seasonings absorbs all the flavors and prevents moisture loss
While the cooking time is longer with sous vide, the actual hands-on preparation is minimal
A great recipe for entertaining company and the sous vide system makes it easy.
Pairs well with virtually all side dishes. A tossed green salad and lemon roasted broccoli combine for a fast and easy meal.
The steak needs no rest time after searing, and can be enjoyed immediately.

spooning seasoned rub on the flat iron steak.

Ingredients for This Sous Vide Steak

Here is a list of the ingredients you will need for the sous vide flat iron steak. Scroll down to the printable recipe card for all the details.

Good quality flat iron steak
Dry beef rub

Prepared flat iron steak in a sous vide bag.

Recipe Highlights for the Flat Iron Steak

Cooking a sous vide steak is perfect for entertaining because you can relax and focus on the other elements of your dinner, knowing that your steak is cooking perfectly. Once all the food is ready, remove the flat iron from the sous vide bag and give it a quick sear. If it takes longer than expected to get the rest of the food ready, just leave the flat iron in the sous vide circulator without worrying that it will be ruined.

Here is a quick overview of the process. Scroll down to the printable recipe card for all the details.

Setting Up the Sous Vide and Preparing the Steak:

Fill the sous vide container with water, attach the heating unit and set it to your desired temperature. We set our unit to 130 degrees F for medium-rare. You should choose the temperature that matches your desired doneness.
Sprinkle the steak on both sides with your desired rub (we used our Santa Maria Rub), rubbing it into the surface.
Optional step -Transfer the steak to the refrigerator for one hour so the rub can penetrate into the steak.
Place the flat iron steak in a vacuum seal bag. Remove the air and seal the bag.

To Cook the Steak:

When the water reaches your desired temperature, submerge the sealed bag with the steak in the water.
Once the steak has finished cooking, you can leave it submerged in the water container for another hour or two. You don’t have to worry about it over-cooking.
Follow the method in the recipe card for searing the steak, depending on if you want it stovetop or grilled.

Seared sous vide flat iron steak on a cutting board.

Top with homemade savory and fresh chimichurri sauce or creamy peppercorn sauce to really take this steak to the next level!

Tips for Success

In order to achieve a good sear and dark crust it is essential to remove any moisture from the surface before the sear. Make sure to pat well with paper towels to remove surface moisture.
On high heat, turning the steak every 15-30 seconds for 1-½ to 2 minutes total will prevent overcooking while getting a rich crust.
If you are using the charcoal grill leave the steak in the water container until the charcoal is lit, spread, and the grill is hot.
The steak does not need a ‘rest’ time after it has been seared!

Recipe Variations

Spicy Steak: If you love some heat, add some crushed red pepper flakes or a sliced jalapeno to the bag before sealing and cooking.
Asian-Style Steak: Create an Asian-inspired marinade with our Japanese marinade. Marinate the steak before cooking for a flavorful twist.
Italian flat iron steak recipe: Create an Italian-inspired dry rub with one teaspoon each of garlic powder, dried oregano, dried basil, and salt.

Serving Suggestions

These side dish recipes complement the flat iron beautifully and elevate your dining experience.

And here are some suggestions for dessert

A platter of sliced sous vide flat iron steak and drizzled with red chimichurri sauce. A dish of red chimichurri sauce in the background.

Helpful Tools

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Some Other Recipes We Are Sure You Will Love:

This Sous Vide Pork Tenderloin is the best way to cook this cut of meat. It results in juicy, moist and tender pork tenderloin every single time! We pair it with a simple cider garlic sauce that is easy to make and will add extra savory flavor to your meal.

Our Sake Marinated Grilled Ribeye Steak is a fusion of bold flavors that soak into an ultra-tender, juicy ribeye. This choice cut of steak is marbled and packed with flavor!

This Smoked London Broil is easy to prepare, and it is just the thing everyone will crave during bbq season! Just marinate in a simple but delicious sauce, then let your smoker do the heavy lifting.

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Sliced flat iron steak on a cutting board.

Sous Vide Flat Iron Steak

This easy sous vide flat Iron Steak is cooked medium-rare and is so tender and full of flavor. Choose your favorite store-brand of beef seasoning rub or do a custom seasoning according to your taste preference.

5 from 6 votes

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Prep Time: 5

Cook Time: 1 30

Additional Time: 1

Total Time: 2 35

Servings: Servings

Calories: 354kcal

Author: Pat Nyswonger

Ingredients

1-½ to 2 pounds flat iron steak
2-3 tablespoons dry beef rub

To Sear the Steak

high smoke point oil such as safflower or refined avocado oil
1 tablespoon butter

Instructions

Prepare the sous vide system:

Fill the sous vide water container with water, attach the heating unit, and set it to your desired temperature. We set our unit to 130°F for medium-rare. You should choose the temperature that you like your steak cooked to.

Prepare the Steak:

Pat the steak dry with a paper towel.
Coat the flat iron on both sides with the rub, rubbing it into the surface. (we used our Santa Maria Rub)
Transfer the steak to the refrigerator for one hour so the rub can penetrate into the steak. (this is an optional step).
Place the flat iron steak in a vacuum-seal bag and seal, removing the air. Optionally, submerge a ziplock bag in water (without submerging the opening) and let the water push all the air out, then seal the bag.

To Cook the Steak:

When the water in the sous vide container reaches your desired temperature, submerge the sealed bag into the water and cook for 1-½ hours.
Once the steak has cooked for 1-½ hours you can leave it submerged in the water container for another hour or two. It will not continue to cook but will give you plenty of time to put the rest of your dinner together.
Finishing/Searing the Steak:We have listed two methods to use when you are ready to finish/sear the steak: either a stove top or a grill. To get a good exterior color without cooking the steak further, you will need the heat to be super-hot. Work quickly, turning the steak every 15 to 30 seconds until you get a deep, rich crust.
When you are ready to sear the steak, remove the bag from the water and transfer the steak to a thick pad of paper towels. Pat the steak with paper towels to remove the surface moisture.

To Finish the Steak on the Stovetop:

Set a heavy-bottomed skillet, such as cast iron, over high heat. Add 1 or 2 tablespoons oil to the skillet, and when it is just beginning to smoke, place the steak in the skillet.
Sear the steak for 15 to 30 seconds, flip it over, and sear for 15-30 seconds. Continue searing each side, turning it over until you have a rich brown crust.
Adding a tablespoon of butter during the last 15-30 seconds will help give a good color and rich flavor to the steak. Do not add the butter sooner, or it will burn and turn bitter.

To Finish the Steak on a Grill:

To sear the steak on a grill, prepare a charcoal or gas grill for high heat. Keep the lid closed for 15 to 20 minutes so the grill grates have time to get super hot.
Cook the steak, turning every 15 to 30 seconds until a rich crust forms on the steak.

Notes

When you slice the steak, it will look as though the steak is overcooked, do not fear! This is a feature of sous vide cooking, and it is only temporary. As the sliced meat sits at room temperature and is exposed to the oxygen in the air, it will begin to "bloom" as the myoglobin in the meat comes in contact with the oxygen. The color gradually turns pink and then red, so that it might appear even more rare than it actually is.
In order to achieve a good sear and dark crust it is essential to remove any moisture from the surface before the sear. If the steak is wet then it will steam instead of sear.
A super-high heat is needed for the sear so you can get a rich color very quickly without further cooking the steak.
Turning the steak every 15-30 seconds for 1-½ to 2 minutes total will prevent overcooking while getting a rich crust.
Be sure to open windows and turn on the vent if you are using the stovetop to finish the steak.
If you are using the charcoal grill leave the steak in the water container until the charcoal is lit, spread, and the grill is hot.
The steak does not need a ‘rest’ time after it has been seared.