Flank steak is lean, flavorful, and fast when treated right. Cook it sous vide and you turn a potentially tough cut into something evenly pink, tender, and slice-friendly every single time. I reach for this method when I want a reliable weeknight main that also impresses when guests arrive.
This recipe keeps things focused: a simple seasoning mix, a precise 135°F bath for a perfect medium-rare, and a quick sear to finish. No long marinades, no guesswork—just steady heat and a hot skillet to build color and flavor.
Below you’ll find the exact ingredient list and the step-by-step method I use at home. I include practical equipment notes, troubleshooting tips, and storage advice so you can make this repeatable and relaxed.
What You’ll Gather
Ingredients
- 32 ounces flank steak — the star of the dish; lean and best sliced thin against the grain.
- 2 teaspoons salt — seasons through the meat; important for even flavor.
- 1 teaspoon pepper — adds a straightforward, bright bite.
- 1 teaspoon garlic powder — gives a savory backbone without wet marinade.
- 1 teaspoon chili flakes — brings gentle heat and a touch of texture.
- 2 tablespoons balsamic vinegar — acidity to balance richness and help the seasoning cling.
- 1 tablespoon Dijon mustard — emulsifies with the vinegar and adds depth.
- 2 tablespoons butter — for a flavorful, quick sear and glossy finish.
Mastering Sous Vide Flank Steak: How-To
- Preheat the sous vide water bath to 135°F.
- In a bowl, combine 2 teaspoons salt, 1 teaspoon pepper, 1 teaspoon garlic powder, 1 teaspoon chili flakes, 2 tablespoons balsamic vinegar, and 1 tablespoon Dijon mustard; stir until a uniform mixture forms.
- Place the 32 ounces flank steak into a vacuum-seal bag. Pour the seasoning mixture over the steak, remove air, and vacuum-seal the bag.
- Submerge the sealed bag fully in the preheated sous vide bath. Cook for 2 hours; you may cook up to 3 hours if needed.
- Remove the bag from the water bath. Open the bag and discard the liquid and any loose spices from the bag. Pat the steak dry with paper towels.
- Heat a cast iron skillet over medium-high heat until hot. Add 2 tablespoons butter and let it melt and foam.
- Add the flank steak to the skillet and sear until browned, about 1–2 minutes per side. Adjust heat if the butter begins to burn.
- Transfer the steak to a cutting board and let it rest for 10 minutes. Slice thinly against the grain and serve.
Why Cooks Rave About It
Sous vide removes the biggest variables: uneven doneness and overcooking. Flank steak responds exceptionally well because the long muscle fibers relax in the gentle, controlled bath, producing uniform tenderness from edge to edge. You get a consistent medium-rare interior with a single, deliberate sear to develop flavor and color.
It’s forgiving, too. The recipe’s window (2–3 hours) gives you a buffer. If dinner runs late, your steak won’t turn into leather five minutes past ideal—just a little more time in the bath. That predictability makes it a favorite for busy cooks who still want restaurant-quality results.
International Equivalents
Looking for similar cuts or approaches around the world? Think of skirt steak (often used in Latin American recipes like carne asada) and bavette or flap steak (popular in French and British cuisines). They have comparable texture and benefit from the same sous vide treatment for tenderness.
The technique mirrors precision grilling methods worldwide: in Brazil, churrasco focuses on quick, high-heat finishing; in France, bistro cooks thinly slice well-seared beef for shared plates. If you can’t find flank, skirt or flap are reasonable substitutes; adjust searing time to match thickness.
Equipment & Tools
Must-haves
- Sous vide immersion circulator — keeps water at a steady 135°F for precise doneness.
- Large pot or container — big enough to submerge your sealed steak fully.
- Vacuum sealer and bags — the recipe uses vacuum sealing; an alternative is a heavy-duty zip-top bag with the water displacement method.
- Cast iron skillet — holds and distributes high heat for an effective, quick sear.
- Paper towels — critical for drying the steak before searing to ensure good Maillard reaction.
Nice-to-haves
- Instant-read thermometer — for reassurance, though sous vide sets the internal temp precisely.
- Tongs — for safe handling during the sear.
- Cooling rack and cutting board — for restful carryover and clean slicing.
Avoid These Traps
Skip these mistakes and your results will be noticeably better.
- Searing wet meat. After sous vide, pat the steak completely dry. Water on the surface prevents browning and creates steam that fights the skillet’s heat.
- Overcrowding the pan. Sear in a hot, open skillet with space around the steak. Crowding drops the pan’s temperature and leads to steaming instead of searing.
- Using too-low searing heat. You need a hot pan and quick contact—1–2 minutes per side—as written. Keep the sear brief to avoid cooking the interior further.
- Skipping rest before slicing. Even after sous vide, a short 10-minute rest keeps juices in the meat and makes slicing cleaner.
Seasonal Spins
Change the sides and finishing touches by season to keep this dish fresh all year.
- Spring: Serve with pea purée or a bright herb salad (parsley, mint, lemon) to cut the steak’s richness.
- Summer: Pair with charred corn, tomato salsa, or a simple chimichurri for freshness and acidity.
- Fall: Roast root vegetables and a balsamic glaze echo the balsamic already in the seasoning mix for warm, cozy flavors.
- Winter: Offer creamy mashed potatoes or a rich mushroom ragout to complement the beefiness.
Chef’s Notes
Two quick technique points that make a big difference: dry thoroughly and slice thin against the grain. The recipe directs discarding the bag liquid—do that. It concentrates flavors but also contains moisture and loose spices that will steam your steak if left on during the sear.
Also, the 135°F target is for medium-rare. If you prefer medium, raise the bath temp slightly (commonly to ~140–145°F) and accept that the texture will be firmer. The 2-hour baseline produces a tender, thoroughly heated center; up to 3 hours is safe and won’t noticeably overcook the steak.
Keep It Fresh: Storage Guide
Leftover cooked flank steak stores very well. Cool to room temperature, then refrigerate in an airtight container for up to 3–4 days. For longer storage, freeze slices or whole cooked steak for up to 2–3 months. Vacuum sealing before freezing preserves texture best.
To reheat without drying, gently warm in a sous vide bath at 120–130°F until heated through, or reheat briefly in a hot skillet with a pat of butter—just enough to restore crust and warmth. Reheating in the oven at low temperature also works but watch closely to avoid dry edges.
Frequently Asked Questions
Can I cook the steak longer than 3 hours? The recipe allows up to 3 hours. Beyond that, flank can begin to change texture—some prefer longer times for very tender results, but the recommended window preserves structure while tenderizing.
What doneness does 135°F give? 135°F produces a classic medium-rare: warm, pink throughout, and tender. If you want a different doneness, raise or lower the bath temp in small increments and experiment with short runs.
Can I use a zip-top bag instead of vacuum sealing? Yes. Use the water displacement method: seal almost all the way, slowly lower the bag into the water to push out air, then seal fully. Make sure the bag material is rated for sous vide temperatures.
How thin should I slice? Cut as thinly as you can against the grain—ideally 1/8- to 1/4-inch slices. Thin slices maximize tenderness on the plate and make the lean flank easier to chew.
Before You Go
Make this the steak you turn to when you want reliable, high-quality results with minimal stress. The method is forgiving, the seasoning is simple, and the payoff—juicy, evenly cooked, richly flavored slices—is worth the small extra step of a water bath. Try it once and you’ll find reasons to repeat it.
If you try the recipe, come back and tell me how you finished it—sides, sauces, or any tweaks you loved. I read every comment and love hearing variations that work in real kitchens.
Sous Vide Flank Steak
Ingredients
Ingredients
- 32 ouncesflank steak
- 2 teaspoonssalt
- 1 teaspoonpepper
- 1 teaspoongarlic powder
- 1 teaspoonchili flakes
- 2 tablespoonsbalsamic vinegar
- 1 tablespoonDijon mustard
- 2 tablespoonsbutter
Instructions
Instructions
- Preheat the sous vide water bath to 135°F.
- In a bowl, combine 2 teaspoons salt, 1 teaspoon pepper, 1 teaspoon garlic powder, 1 teaspoon chili flakes, 2 tablespoons balsamic vinegar, and 1 tablespoon Dijon mustard; stir until a uniform mixture forms.
- Place the 32 ounces flank steak into a vacuum-seal bag. Pour the seasoning mixture over the steak, remove air, and vacuum-seal the bag.
- Submerge the sealed bag fully in the preheated sous vide bath. Cook for 2 hours; you may cook up to 3 hours if needed.
- Remove the bag from the water bath. Open the bag and discard the liquid and any loose spices from the bag. Pat the steak dry with paper towels.
- Heat a cast iron skillet over medium-high heat until hot. Add 2 tablespoons butter and let it melt and foam.
- Add the flank steak to the skillet and sear until browned, about 1–2 minutes per side. Adjust heat if the butter begins to burn.
- Transfer the steak to a cutting board and let it rest for 10 minutes. Slice thinly against the grain and serve.
Equipment
- Sous Vide Immersion Circulator
- water bath
- vacuum sealer
- vacuum-seal bag
- Bowl
- Cast-Iron Skillet
- Tongs
- Paper Towels
- Cutting Board
Notes
Storage:Store the cooled leftover flank steak in an airtight container or sealed plastic bag and refrigerate for up to 3 or 4 days.
Steak water temperature: Rare: Cook at 125°F (51.7°C)Medium-Rare: Cook at 130°F (54.4°C)Medium: Cook at 140°F (60°C)Medium-Well: Cook at 150°F (65.6°C)Well-Done: Cook at 160°F (71.1°C)
