Soups & Stews
This beef and string beans stir fry delivers crisp-tender beef and vibrant green beans in just 20 minutes—perfect for weeknight dinners that feel restaurant-quality. The secret lies in high-heat wok searing, which locks in juices while creating that signature smoky wok hei flavor.
I've perfected this technique after years of testing, ensuring every bite is packed with savory depth and satisfying texture.
The recipe balances protein-rich beef strips with crisp-tender string beans, all tossed in a flavorful sauce that's sweet, tangy, and just slightly spicy. We start with a quick marinade for the beef—just soy sauce, garlic, and a touch of cornstarch—to guarantee that perfect sear.
The string beans get a quick blanch to preserve their vibrant color and crisp texture before joining the beef in the wok.
What you'll end up with is a dish that's foolproof yet impressive—golden-brown beef with caramelized edges, bright green beans that stay crisp, and a sauce that clings perfectly to every bite.
The aroma alone will have everyone gathering at the table, and the flavors are balanced just right: savory, slightly sweet, with a hint of spice that lingers.
Serve this stir fry over steamed jasmine rice for a complete meal, or pair it with noodles for extra heartiness. The recipe scales easily for crowds, and leftovers reheat beautifully while maintaining that crisp-tender texture. Let's get cooking—your weeknight dinners just got an upgrade.
Ingredients for beef and string bean stir fry
Quick grocery list for restaurant-style stir fry that's ready in 20 minutes.
| Ingredient | Amount | Notes |
|---|---|---|
| Flank Steak 🥩 | 1 lb | Thinly sliced against grain |
| String Beans 🥦 | 1 ½ lbs | Trimmed, cut into 2-inch pieces |
| Low-Sodium Soy Sauce 🥫 | ¼ cup | For marinade and sauce |
| Cornstarch 🌾 | 1 tbsp | For beef coating |
| Garlic Cloves 🧄 | 4 cloves | Minced for marinade |
| Sesame Oil 🫒 | 1 tbsp | For aroma |
| Brown Sugar 🍯 | 2 tbsp | Light or dark |
| Rice Vinegar 🍶 | 2 tbsp | For tangy balance |
| Sriracha 🌶️ | 1 tbsp | Adjust for heat |
| Vegetable Oil 🫒 | 2 tbsp | High smoke point |
| Green Onion 🧅 | 3 whole | Sliced for garnish |
| Sesame Seeds 🌾 | 1 tsp | Toasted for crunch |
| Salt 🧂 | ½ tsp | Kosher or sea salt |
| Black Pepper 🌶️ | ¼ tsp | Freshly ground |
The beef is everything here. Flank steak slices perfectly against the grain for that signature tender bite, and you can usually find it pre-sliced at Costco or the butcher counter. Look for good marbling—it'll keep the meat juicy during that high-heat sear. String beans should be bright green and crisp; Trader Joe's has great pre-trimmed ones, but any fresh string beans work. Pro tip: slice them into even 2-inch pieces so they cook uniformly. The garlic? Freshly minced makes all the difference—don't use that pre-minced jar stuff.
No soy sauce? Coconut aminos works in a pinch, though the flavor won't be identical. Running low on sesame oil? Toasted sesame seeds can be ground into a paste as a substitute (just add a splash of water). The brown sugar can be swapped for honey or maple syrup if you're avoiding refined sugar. For extra heat, swap sriracha for chili garlic sauce. And if you're short on time, those pre-cut stir-fry veggie mixes at Walmart or Target work great—just skip the blanching step since they're already trimmed.
This dish reheats beautifully—just toss with a splash of water and heat through. Keeps for 3-4 days in the fridge, though the texture starts to soften after day 2. For meal prep, portion into containers with rice and store separately. Freezes well for up to 2 months if you want to make a big batch. The sesame seeds and green onions are best added fresh after reheating, so save them for garnish. Trust me, that extra minute of toasting the sesame seeds before adding them makes all the difference.
Why You'll Love This Recipe
- One-Pan Magic: I swear by this for nights when I don’t want to wash a million dishes—just sear the steak, toss in the beans, and let the garlic and soy sauce work their magic in one skillet. Boom. Done.
- Umami Bomb: That cornstarch-coated steak? Crispy outside, tender inside, with a savory punch from the low-sodium soy sauce—it’s the kind of flavor that makes you reach for seconds without thinking.
- Lunchbox Hero: Between us, this is my go-to for meal prep: pack the leftovers with rice, and it’s a satisfying lunch for days. (Yes, even on a Tuesday when you’re not feeling inspired.)
- Budget Win: Flank steak stretches far, string beans are cheap, and a little soy sauce goes a long way—this feeds four for under $15. Frugal? Absolutely. Delicious? Even more so.
Step-by-step instructions for wok-seared beef and string beans
Here's how to create crisp-tender beef and vibrant string beans in one fast, flavorful wok session.
Prep and Marinate the Flank Steak
Slice the 1 lb flank steak thinly against the grain into ¼-inch thick strips. This ensures maximum tenderness when cooked quickly. Transfer to a bowl and add the 0.25 cup low-sodium soy sauce, 2 tbsp brown sugar, 2 tbsp rice vinegar, 1 tbsp sriracha, 4 minced garlic cloves, and 0.5 tsp salt. Mix well until the steak is evenly coated.
Let it marinate for at least 15 minutes (30 minutes for deeper flavor). While it marinates, trim the 1.5 lbs string beans and cut them into 2-inch pieces. Blanch the beans in boiling water for 1 minute, then immediately plunge into ice water to stop cooking. This preserves their vibrant color and slight crunch.
Coat the Beef and Prep the Wok
Remove the steak from the marinade (reserve the marinade for later) and pat it dry with paper towels. In a small bowl, combine the 1 tbsp cornstarch with 0.25 tsp black pepper. Toss the steak strips in this mixture until evenly coated—this creates a crispy exterior when seared.
Heat a wok or large skillet over high heat until it's smoking hot. Add 2 tbsp vegetable oil and swirl to coat the bottom evenly. The oil should shimmer but not smoke excessively—this is your signal it's ready for the beef.
Wok-Sear the Beef to Perfect Doneness
Working in batches if needed, add the coated steak strips to the wok. Stir-fry for 2-3 minutes until the edges turn deep golden brown and the beef reaches 145°F internally. Remove the beef and set it aside on a plate.
In the same wok, add a little more vegetable oil if needed, then toss in the blanched string beans. Stir-fry for 2-3 minutes until they're heated through and slightly crisp-tender. Don't overcook—they should still have a slight bite.
Combine and Finish with Sauce
Return the beef to the wok along with the reserved marinade. Add 1 tbsp sesame oil and toss everything together for 1-2 minutes until the sauce thickens slightly and coats the beef and beans. The mixture should be glossy with just enough sauce to cling to everything.
Taste and adjust seasoning if needed—add a splash of water if the sauce is too thick. Garnish with sliced 3 green onions and toasted 1 tsp sesame seeds just before serving. Serve immediately over steamed rice for the perfect balance of textures and flavors.
Pro Tips For Making Beef And String Bean Stir Fry
- SLICE THIN, COOK FAST: Flank steak fights back when overcooked—cut it against the grain in paper-thin slices (⅛-inch max) and sear for just 30-45 seconds per side. I used to drag out the cooking, and the meat turned chewy. High heat and quick timing keep it tender.
- TRIM BEANS, NOT TIME: String beans lose their snap when overcrowded—trim the ends, then blanch them for 2 minutes in boiling water before stir-frying. This jumpstarts tenderness and prevents a mushy pile. (Yes, it’s an extra step, but your stir-fry will actually look like one.)
- SALT THE SOY SAUCE: Low-sodium soy sauce is a flavor ghost if you don’t boost it. Mix in ½ teaspoon of sugar and a pinch of black pepper per tablespoon, then let it sit while you prep. I learned this after a bland stir-fry made me question my life choices.
- GARLIC FIRST, THEN BEANS: Cook minced garlic in the wok until it’s just golden—about 30 seconds—before adding the beef. Then toss in the beans. This builds flavor without burning, and the garlic’s aroma infuses the meat. (Pro move: Smash the cloves with the side of your knife first.)
Perfect pairings for this dish
Rice Pairings
Jasmine rice is my go-to base for this stir fry—its delicate floral aroma complements the savory beef and bright beans beautifully. Cook 1 cup jasmine rice with 1.5 cups water for perfectly fluffy grains.
For extra richness, try forbidden black rice, which adds a subtle earthy note that pairs wonderfully with the dish's bold flavors. 🍚
Short-grain sushi rice works too, especially if you like a stickier texture. Just rinse it thoroughly before cooking to remove excess starch. I also love serving this stir fry over cauliflower rice for a low-carb option—it soaks up the sauce while keeping the dish light and fresh.
Noodle Alternatives
Swap rice for egg noodles or udon noodles if you prefer a heartier meal. Cook the noodles al dente, then toss them with the stir fry for 1-2 minutes to absorb the sauce. I recommend fresh rice noodles for a chewy texture that stands up to the beef's richness.
For a gluten-free option, use rice noodles—just
A simple steamed bok choy adds another layer of freshness to the plate. Toss it with a pinch of sesame oil and soy sauce before serving. Quick-pickled cucumbers also work wonders—they cut through the richness with their bright, tangy crunch. For a warm side, try garlic green beans—blanch them for 2 minutes, then toss with minced garlic and toasted sesame seeds. The double green bean treatment makes this a complete meal with minimal effort. A crisp green tea, like japanese sencha, cleanses the palate between bites and complements the dish's savory-sweet balance. For something lighter, try sparkling water with lime—the effervescence helps reset your taste buds. If you prefer alcohol, a dry sake—especially a junmai ginjo—pairs beautifully with the umami-rich flavors. For beer lovers, a light lager** like Asahi or Sapporo keeps the meal refreshing without overpowering the dish.Vegetable Sides
Drink Pairings
Nutrition facts
Frequently asked questions
Can I substitute flank steak with another cut of beef?
Yes! Sirloin or ribeye work well—just slice them ¼-inch thick against the grain for tenderness. Chuck roast is cheaper but needs longer marinating (1-2 hours) and slower cooking (medium heat) to avoid toughness. Avoid fatty cuts like brisket—they won't sear properly in a wok.
Why do my string beans turn mushy?
Overcooking is the #1 culprit! Stir-fry them for only 2-3 minutes over high heat—they should stay bright green with a slight crunch. Start blanching time at 1 minute (not 2+), and use ice water immediately to stop cooking. Also, crowding the wok lowers heat—work in batches if needed.
How do I make this dish spicier?
Double the 1 tbsp sriracha and add ½ tsp red pepper flakes to the marinade. For extra heat, toss in 1 tbsp chili crisp or 1 chopped Thai chili during the final stir-fry. Serve with sriracha mayo (mix mayo + sriracha) on the side for dipping.
Can I make this ahead of time?
Yes! Cook the beef and beans separately, then refrigerate in airtight containers for up to 3 days. Reheat gently in a skillet with 1 tsp oil over medium heat for 3-4 minutes. The texture won't be as crisp, but flavors stay intact. Save garnishes (sesame seeds, green onions) for fresh topping.
What's the best way to reheat leftovers?
Microwaving kills the wok hei flavor, so always use a skillet! Heat 1 tsp oil over medium-high heat, add the stir fry, and toss for 2-3 minutes until hot. Add 1 tsp water to loosen the sauce. For extra crispiness, sear the beef separately first, then combine with the beans.