How to cook easy, tender Sous Vide Flank Steak with a flavorful soy marinade and dipping sauce. This is a perfect make-ahead dinner for entertaining or a busy weeknight.
About Sous Vide Flank Steak
This flank steak recipe is packed with deep umami flavor. Thanks to the long, slow sous vide cooking technique, every bite of your steak is packed with flavor from your marinade.
And you won’t let that marinade go to waste either! Turn it into a thick, slightly sweet and sticky sauce after cooking the steak. Then drizzle your teriyaki sauce over the whole plate or serve it on the side for dipping.
Add a sprinkle of fresh green scallions to complete this meaty, savory, and always crowd-pleasing flank steak dinner recipe.
- Light soy sauce. This is the base of your steak marinade and sauce. Choose low-sodium or light soy sauce to make sure the dish doesn’t turn too salty.
- Apple juice. Choose unsweetened, which adds just a bit of natural sweetness without overpowering the other sauce ingredients.
- Mirin. This is a Japanese rice wine that’s sweeter and lower in alcohol than sake. It’s a pantry staple for Japanese cooking as it’s a great way to loosen up sauces and add subtle tangy sweetness.
- Sesame oil. A little goes a long way when it comes to sesame oil. This is the key to slowly tenderizing the meat as it cooks sous vide.
- Sugar. Sugar helps caramelize the meat when you sear it after removing it from the water bath.
- Flank steak. A naturally lean cut, flank steak benefits from long, slow cooking. This cut can be tough, but the low-temperature, even application of heat from sous vide cooking helps tenderize the connective tissue in the meat. The long cooking time also helps the meat soak up even more marinade flavor.
- Scallions. These add flavor to the steak sauce and an attractive garnish on top of the dish.
- Carrots and onion. Dice these veggies nice and small, as you want them to add flavor to your simmering sauce quickly. They’ll eventually be strained out, so don’t worry too much about pretty knife cuts.
- Cornstarch. To thicken your sauce, make a quick slurry with cornstarch and cold water. Don’t worry, you won’t taste the two teaspoons of cornstarch in the finished sauce.
- Olive oil and butter. These cooking fats are the key to achieving a beautifully even, dark brown sear on your sous vide flank steak.
How Long to Cook Sous Vide Flank Steak
For perfectly tender flank steak, set your sous vide to 129°F/53°C.
Cook the meat for 10 hours for juicy, easy-to-slice steak that’s still a bit pink in the center.
How to Make Sous Vide Flank Steak
You can easily pop a trimmed flank steak in an airtight bag in your sous vide for 10 hours at 129°F/53°C and come back to tender and buttery steak. But I wanted to elevate the meat with a savory, umami-packed marinade and sauce.
To make this recipe, pack your trimmed flank steak into a Ziploc or vacuum-sealed bag with a soy sauce marinade and fragrant aromatics. Submerge the bag fully in the water bath when it reaches temperature, and walk away for 10 hours. While you spend time with family or have a productive workday, your sous vide wand is doing all the work.
Come back to reveal juicy, tender steak that just needs a fast sear in a hot skillet, and dinner is ready. You can also put all those flavorful juices left from the marinade to good use by simmering them down into a sticky-sweet teriyaki-style steak sauce.
A few helpful tips for this recipe:
- Be sure the steak is submerged in water the whole cooking time. You can place a plate or other weight on top of the bag to keep it from floating to the surface if necessary.
- When you add the cornstarch slurry to the teriyaki sauce, use a wire whisk to thoroughly incorporate the slurry into the sauce, making sure no lumps remain.
- Once the slurry is mixed in, return the sauce to a simmer to cook off any raw starch flavor.
- Sous vide wand. This is the most important piece of cooking equipment for this recipe. There are several great options available at affordable prices, and you won’t regret the investment. A sous vide is one of the best ways to prepare perfectly-cooked meat, vegetables, fish, and even desserts at home.
- Large container or pot. A big stockpot like you’d use to cook corn on the cob or pasta is perfect for this recipe. It just needs to be big enough to submerge the meat in water.
- Saucepan. Use a medium saucepan to simmer your steak sauce after the sous vide finishes.
- Whisk. Be sure to use a wire whisk to incorporate the cornstarch slurry into your sauce, breaking up any lumps.
- Large skillet. I love to use my cast-iron skillet to get a beautiful sear on the steak after sous vide cooking.
- Cutting board. You’ll want to allow the steak to rest for 5 to 10 minutes after searing and before slicing.
Wondering what to serve with your beautifully seared and sliced sous vide flank steak? I like to pair it with a starch and a vegetable side dish to complete the meal, such as:
- Steamed brown or white rice
- Slimmed-Down Roasted Broccoli
- Berry Spinach Salad with Feta and Spiced Pecans
- Spiral Sweet Potato Oven Fries
Storage & Leftovers
Store leftover sous vide flank steak in the fridge for up to three days. It’s a delicious and healthy salad topper or sandwich filler for lunch. Or serve up a hearty breakfast of steak and eggs the next morning.
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Sous Vide Flank Steak
- ⅓ cup light soy sauce
- 3½ tablespoons unsweetened apple juice
- 2 tablespoons mirin
- 1 teaspoon sesame oil
- ½ cup sugar
- ¼ teaspoon ground pepper
- 1½ pounds flank steak trimmed
- 2 garlic cloves crushed
- 3 scallions sliced and divided
- ⅓ cup diced carrots
- ¼ cup diced white onion
- 2 teaspoons cornstarch
- 1 tablespoon olive oil
- 1 tablespoon unsalted butter
- Flaky salt
- In a large pot or container with a sous vide, heat 8 liters of water to 129°F/53°C.
- In a medium bowl, combine the soy sauce, apple juice, mirin, sesame oil, sugar, and pepper.
- Pack the flank steak into a sous vide bag with the marinade and the crushed garlic. You can marinate the steak in the fridge overnight or start cooking right away.
- Cook the steak in the water bath for 10 hours.
- Remove the cooked flank steak from its bag and pour all of the liquid into a medium pot. Add the sliced scallion whites (reserving the green part for garnish), carrots and onion. Bring to a boil and cook over medium heat for 10 minutes.
- Meanwhile, in a small bowl, whisk the cornstarch into two tablespoons of cold water. Whisk the cornstarch slurry into the simmering sauce. Continue cooking for two more minutes, until the sauce is thickened. Strain the sauce and discard the solids.
- Pat the flank steak dry with paper towels. In a large skillet over high heat, heat the butter and olive oil until it begins to smoke. Sear the flank steak for one and a half minutes per side, until a seared crust forms. Immediately remove the steak from the skillet and allow it to rest for two minutes.
- Slice the steak thinly, top with the reserved scallion greens and serve with the sauce.