I like this recipe because it comes together quickly while still tasting like something I put real care into. I appreciate how the marinade keeps the flank steak tender, and I enjoy the balance of salty, slightly sweet, and savory flavors. I also love that I can prep the vegetables while the beef marinates, which makes the whole cooking process smooth and efficient.
Ingredients
(Note: All ingredient amounts are listed in the recipe card below.)
For the Beef ▢2 tablespoons soy sauce or lite tamari, or coconut aminos ▢1 tablespoon mirin or white cooking wine ▢1 tablespoon cornstarch ▢1 teaspoon sugar or sugar substitute ▢1 pound flank steak thinly sliced ▢1 tablespoon sesame oil for cooking
For the Stir-Fried Vegetables ▢1 medium green bell pepper chopped ▢1 medium red bell pepper chopped ▢1 medium white onion thinly sliced ▢¼ cup oyster sauce ▢2 green onions sliced
Directions
I start by whisking the soy sauce, mirin, cornstarch, and sugar together in a large bowl until smooth. I add the sliced flank steak, toss it well to coat, then cover and let it marinate for at least 20 minutes.
Once the marinating time is up, I heat the sesame oil in a large skillet over medium-high heat. When the oil is hot, I add only the steak, leaving the excess marinade behind, and cook it for about 5 minutes until it turns golden brown. I transfer the cooked beef to a plate and wipe out the skillet.
I add the green bell pepper, red bell pepper, and onion to the skillet and cook them for 2 to 3 minutes until just tender. I stir in the oyster sauce and let it come to a gentle simmer. I return the beef to the skillet, add the green onions, and stir everything together until well combined. I serve it warm with my favorite sides.
Servings and Timing
I make this recipe for 4 servings. I usually plan about 15 minutes for prep time, 20 minutes for marinating, and 15 minutes for cooking. From start to finish, I have dinner ready in about 50 minutes.
Variations
I sometimes swap flank steak for skirt steak or sirloin when that’s what I have on hand. When I want extra vegetables, I like adding broccoli florets or snap peas. If I’m craving heat, I stir in a little chili garlic sauce or red pepper flakes at the end.
Storage/Reheating
I store leftovers in an airtight container in the refrigerator for up to 3 days. When reheating, I prefer warming it gently in a skillet over medium heat with a splash of water to keep the sauce from thickening too much. I also reheat it in the microwave in short intervals, stirring in between.
FAQs
Can I make this recipe ahead of time?
I sometimes prepare the marinade and slice the vegetables ahead, but I prefer cooking everything fresh for the best texture.
What cut of beef works best?
I use flank steak because it stays tender when sliced thin and cooked quickly.
Why should I slice the steak across the grain?
I slice across the grain because it shortens the muscle fibers and keeps the beef tender.
Can I use frozen beef?
I can use frozen beef as long as I fully thaw it and pat it dry before marinating.
Is oyster sauce very salty?
I find oyster sauce savory and slightly sweet, but not overpoweringly salty when balanced with vegetables.
Can I make this gluten-free?
I make it gluten-free by using gluten-free tamari or coconut aminos and a gluten-free oyster sauce.
What sides go well with this dish?
I like serving it with steamed rice, cauliflower rice, or simple noodles.
Can I double the recipe?
I double the recipe often, but I cook the beef in batches so it browns properly.
How do I keep the vegetables crisp?
I cook the vegetables quickly over high heat so they stay tender-crisp instead of soft.
Can I reduce the sugar?
I sometimes reduce or omit the sugar, especially if I’m using a naturally sweet oyster sauce.
Conclusion
I keep this beef with oyster sauce in regular rotation because it delivers big flavor without complicated steps. I enjoy how tender the beef turns out and how the sauce coats everything perfectly. It’s a dependable, satisfying meal that I’m always happy to make again.
Tender flank steak stir-fried with colorful vegetables and coated in a rich, savory oyster sauce for a fast, comforting meal that tastes better than takeout.
Ingredients
2 tablespoons soy sauce or lite tamari or coconut aminos
1 tablespoon mirin or white cooking wine
1 tablespoon cornstarch
1 teaspoon sugar or sugar substitute
1 pound flank steak, thinly sliced across the grain
1 tablespoon sesame oil
1 medium green bell pepper, chopped
1 medium red bell pepper, chopped
1 medium white onion, thinly sliced
1/4 cup oyster sauce
2 green onions, sliced
Instructions
In a large bowl, whisk together the soy sauce, mirin, cornstarch, and sugar until smooth.
Add the sliced flank steak to the marinade, toss to coat well, cover, and marinate for at least 20 minutes.
Heat the sesame oil in a large skillet over medium-high heat.
Add the marinated beef to the hot skillet, leaving excess marinade behind, and cook for about 5 minutes until golden brown. Transfer the beef to a plate and wipe out the skillet.
Add the green bell pepper, red bell pepper, and onion to the skillet and stir-fry for 2–3 minutes until just tender.
Stir in the oyster sauce and bring to a gentle simmer.
Return the beef to the skillet, add the green onions, and stir until everything is well coated and heated through.
Serve warm with rice, noodles, or your favorite side.
Notes
Slice the beef across the grain to keep it tender.
Cook the beef in batches if doubling the recipe to ensure proper browning.
Add chili garlic sauce or red pepper flakes for extra heat.
Broccoli or snap peas make great vegetable additions.
