Description
This Beef Onion Stir-fry is a quick and flavorful Asian-inspired dish featuring tender flank steak and sweet small onions seared to perfection and coated in a savory, slightly sweet sauce. Marinated for enhanced tenderness and cooked in a hot wok, this stir-fry balances umami from soy and oyster sauces with a touch of ketchup and sesame oil, creating a delicious weeknight meal that pairs perfectly with steamed rice.
Ingredients
Scale
Beef Marinade
- 1 pound flank steak, thinly sliced against the grain
- 1/4 teaspoon baking soda
- 1 teaspoon cornstarch
- 1 teaspoon neutral oil (vegetable or canola)
- 1 teaspoon oyster sauce
- 1 tablespoon water
Sauce
- 1 tablespoon light soy sauce
- 1 teaspoon dark soy sauce
- 2 teaspoons ketchup
- 2 teaspoons oyster sauce
- 1/4 teaspoon sugar
- 1/4 teaspoon sesame oil
- 1/4 cup water
Vegetables and Cooking Oil
- 10 ounces small onions, sliced into wedges (about 3 small onions)
- 2 tablespoons oil, divided (for cooking)
Instructions
- Marinate the Beef: In a medium bowl, combine the thinly sliced flank steak with baking soda, cornstarch, 1 teaspoon oil, oyster sauce, and 1 tablespoon water. Mix thoroughly so the beef absorbs the marinade evenly. Let it rest for at least 15 minutes, or up to 30 minutes if time allows, to enhance tenderness.
- Prepare the Sauce: In a small bowl, whisk together light soy sauce, dark soy sauce, ketchup, oyster sauce, sugar, sesame oil, and 1/4 cup water. Set this sauce mixture aside to use later in the stir-fry.
- Cook the Beef: Heat a wok over high heat until it begins to smoke. Add 1 tablespoon of oil and carefully arrange the marinated beef in a single layer across the wok’s surface. Let it sear without stirring for 30 seconds to 1 minute, allowing browning to occur. Then, stir-fry the beef for another 15 to 30 seconds until it is about 75% cooked. Remove beef from the wok and set aside.
- Stir-fry the Onions: Add the remaining tablespoon of oil to the hot wok, then add the onion wedges. Stir-fry over high heat for 60 to 90 seconds until the onions are seared and slightly blistered but still retain some crunch. Remove onions from the wok and set aside with the beef.
- Combine and Finish: Pour the prepared sauce into the wok and bring it to a simmer, letting it bubble for about 15 seconds to thicken slightly. Return the beef and onions to the wok, stir-frying everything together for approximately 30 seconds to coat the ingredients evenly with the sauce and heat through. Serve immediately, ideally over steamed rice.
Notes
- For even thinner slices, partly freeze the flank steak before slicing against the grain.
- Marinating for up to 30 minutes tenderizes the beef further, but do not exceed this time to avoid texture changes.
- Adjust the amount of ketchup and sugar to taste for a sweeter or tangier profile.
- Use a wok or a heavy-bottomed skillet for best stir-fry results.
- Serve with steamed jasmine or basmati rice to complement the sauce.
