Mongolian Sous Vide Flank Steak

Learn how to make the most tender Mongolian Sous Vide Flank Steak using one of our favorite kitchen gadgets, the Sous Vide! 

Prep: 15 minutesCook: 24 hoursTotal: 24 hours 15 minutes
Fat 14 Carbs 12 Protein 27
Yield 6 servings 1x


  • 1.5 lbs. flank steak
  • 1/2 cup tamari (or soy sauce)
  • 1/4 cup maple syrup
  • 1/2 tablespoon fresh grated ginger
  • 3 cloves garlic, minced
  • 1/2 teaspoon red pepper flakes
  • salt and pepper, to taste
  • 2 tablespoons olive oil or butter
  • 1 tablespoon cornstarch


  1. First, prepare your Sous Vide by filing a 6-8 quart pot with water. Connect your sous vide to the pot and set the temperature to 132ºF.
  2. Next, place tamari, maple syrup, ginger, garlic, red pepper flakes, salt, and pepper in a bowl. Mix well.
  3. Place flank steak and tamari mixture in a BPA-free vacuum seal bag. Seal the bag and gently massage the meat until it is evenly coated with tamari mixture. Alternatively, you can use a Stasher bag or plastic bag. Just make sure to remove as much air as possible.
  4. Next, vacuum seal your flank steak and place into the pot.
  5.  Let Mongolian Sous Vide Flank Steak cook for 5-24 hours. We highly recommend letting it sit for the full 24 hours as it will come out extremely tender.
  6. Once the flank steak is fully cooked, remove from pot.
  7. Heat a castiron skillet over medium/high heat. Add olive oil to the cast iron skillet. When olive oil is fragrant, place the flank steak in the cast iron. Sear for one minute on each side.
  8. Remove from pan and set aside.
  9. Prepare the Mongolian beef sauce by pouring the juices from your sous vide bag into a medium saucepan and add 1 tablespoon of cornstarch. Bring to a boil, reduce heat, and let simmer for 5 minutes or until thickened.
  10. Slice flank steak and serve over rice and veggies. Pour sauce over the top of the meat and enjoy!

Tips & Notes

  • We cooked our sous vide flank steak for 24 hours, however, you can cook it for as short as 5 hours. The longer it cooks, the more tender it will be.

Nutrition Facts

Serving Size: 1/6 Calories: 279 Sugar: 8 Sodium: 1417 Fat: 14 Carbohydrates: 12 Fiber: 0 Protein: 27
Author: Lee HershCategory: DinnerMethod: Sous VideCuisine: Mongolian

Keywords: Sous Vide Flank Steak