Flank steak is one of my favorite cuts to sous vide. This lean, sometimes a little on the tough side, steak benefits from a low and slow cook and a hot sear. I love to do an herby salt to season this steak, but a marinade is also a great way to go. For the perfect medium-rare flank steak, cook at 129 degrees F for 2-4 hours.
Sous vide is best known in association with beef cuts (well, and the infamous egg bites) and for good reason! Sous vide is the best method for cooking flank steak because it’s near impossible to overcook and even better, tougher cuts like flank steak can be cooked low and slow, tenderizing the meat, too.
How to Season Flank Steak
You really can’t go wrong when it comes to seasoning your flank steak! A jarred seasoning blend, a marinade, or even just salt and pepper are great. If you’re looking for more inspiration, make sure to grab a copy of my cookbook, Sous Vide Meal Prep, which is chock-full of marinade, sauce, and rub recipes.
Sous Vide Meal Prep
This cookbook outlines my entire method for keeping your freezer stocked with ready to sous vide meals (and some great recipes to boot!).
For this recipe, I’m using an herbed salt, which is as truly as simple as combining chopped fresh oregano and kosher salt (I prefer Diamond Crystal). Feel free to swap the oregano with any other “hard” herb, like:
- Rosemary
- Thyme
- Sage
Flank Steak Time and Temperature
When it comes to steak, I like to keep lean cuts on the rare side of medium rare and fattier cuts closer to medium. My go-to temperature is 129 degrees F for 2-4 hours, but you do you!
| Result | Temperature | Time |
|---|---|---|
| Rare | 123 – 127 degrees F | 2-4 hours |
| Medium Rare (my favorite) | 128 – 134 degrees F | 2-4 hours |
| Medium | 135 – 140 degrees F | 2-4 hours |
| Well Done | 141-150 degrees F | 2-4 hours |
If you can’t overcook it, why do I recommend not cooking longer than 4 hours? Even though the interior will still be red, you can over-tenderize the meat, making it mushy. As long as you stay under 4 hours, you’ll avoid this. Even though as short as 1 hour can be fine for thinner cuts of steak, I recommend at least 2 for flank steak to tenderize this tough cut well.
How to Make Sous Vide Flank Steak
This recipe is incredibly easy. Feel free to use whatever seasoning or marinade you want to make it your own – the method will still stand.
Start by scoring the steak. This is done by using a sharp pairing knife and dragging it diagonally one way across the steak, then the other way. Flip the steak over and repeat.
Next, season the steak – I’m simply using a mixture of chopped fresh oregano and kosher salt (I prefer Diamond Crystal). You can add more herbs to the mix if you’d like or swap other “hard” herbs like rosemary, thyme, or sage. Don’t be shy with this seasoning!
Add to a vacuum seal bag and use a vacuum sealer to seal. No vacuum sealer? No sweat. Try one of these other air removal methods.
Once it’s all sealed up, add it to a water bath preheated to your desired temp with an immersion circulator and cook for 2-4 hours.
Once the steak is done sous viding, remove it from the water bath and the vacuum seal bag and pat it completely dry with paper towels or clean dish towels. The less moisture, the better the sear.
Heat ghee (or another high heat fat of choice) in a smoking hot cast iron skillet over high heat. Add the steak and sear on each side until well browned, about 30 seconds to 1 minute.
Before serving, slice the flank steak into slices against the grain and sprinkle with a little more herby salt. I love to make a chimichurri to serve with this flank steak!
Sauces and Sides
This steak is one of those things you’ll stand over the cutting board grabbing bites of, but to make it a complete meal, here are some ideas! I also have a full post of steak sides for you to keep on hand for these situations.
Sauces:
Sides:
Common Questions
Yes! To cook flank steak from frozen, the minimum cook time should be 2.5 hours.
You sure can. I recommend another “hard” herb, like rosemary, thyme, or sage.
In my experience, it’s difficult to get as good a sear on the grill. You’ll risk overcooking it, but it can be done if you can get your grill incredibly hot. Make sure to let it preheat for awhile before searing.
You can also view this recipe as a step-by-step web story here.
Get the Recipe:
Herb Crusted Sous Vide Flank Steak
Ingredients
- 2 tbsp kosher salt
- 1 tbsp finely chopped fresh oregano
- 1 1/2 lbs flank steak
- 2 tbsp ghee, for searing
Instructions
- Preheat water bath using immersion circulator to your desired temperature. 123-127 F for rare, 128-134 F for medium rare, 135-140 F for medium, 141-150 F for well done. I prefer 129 degrees F.
- Combine the kosher salt and oregano in a small bowl. Set aside.2 tbsp kosher salt, 1 tbsp finely chopped fresh oregano
- Using a sharp pairing knife, score the flank steak by dragging the tip of the knife diagonally across the surface of the steak in one direction, then in the opposite direction. Repeat on the other side of the flank steak.1 1/2 lbs flank steak
- Season the scored flank steak with the kosher salt oregano mixture well on both sides. You likely will not use all the salt. Remaining salt can be added to a jar and stored for future use.
- Add the steak to a vacuum seal bag and vacuum seal. If you don't have a vacuum sealer, add to a freezer-safe zipper-top gallon-sized bag and use another air removal method.
- Add the vacuum sealed steak to the preheated water bath and cook for 2-4 hours.
- When the steak is done cooking, remove the bag from the water bath and the steak from the bag. Using paper towels or a clean dish cloth, pat it dry on both sides.
- Heat a cast iron skillet over high heat until smoking. Add the ghee. Sear the steak on both sides until a deep brown, 30 seconds to 1 minute.2 tbsp ghee
- Slice the steak into 1/2 inch slices against the grain. Sprinkle with a little of the remaining salt and serve.
Notes
- Swap the herby salt for any rub or marinade that you want.
- Don’t have oregano? You can use any other “hard” herb in its place (rosemary, thyme, or sage).
- Serve this flank steak with chimichurri for a real winner of a meal!
Followed the recipe exactly, and it was flank steak perfection! Extremely tender and a great beefy flavor. Our new go-to recipe!
I’m so glad!!! Nothing like sous vide flank steak.
can you do more than one steak flank in the pot at a time? in separate bags?
Yes, you can certainly cook more than one flank steak at a time! Separate bags is the way to go. No need to make any adjustments to the recipe.