Ingredients:

  • 1 pound (450g) beef sirloin steak, thinly sliced against the grain
  • 1 tablespoon soy sauce (low sodium preferred)
  • 1 tablespoon cornstarch (cornflour, UK)
  • 1 teaspoon sesame oil
  • 1/2 teaspoon ground black pepper
  • 1 tablespoon vegetable oil
  • 1 tablespoon vegetable oil
  • 1 large onion, thinly sliced
  • 1 red bell pepper, seeded and sliced
  • 1 green bell pepper, seeded and sliced
  • 1 yellow bell pepper, seeded and sliced (optional, for extra color)
  • 2 cloves garlic, minced
  • 1 inch ginger, minced
  • 1/2 cup (120ml) beef broth (or chicken broth)
  • 2 tablespoons soy sauce (low sodium preferred)
  • 1 tablespoon oyster sauce (optional, but adds depth of flavor)
  • 1 tablespoon brown sugar (light or dark)
  • 1 tablespoon cornstarch (cornflour, UK)
  • 1 tablespoon rice vinegar (or white vinegar)
  • 1 teaspoon sesame oil
  • 1/2 teaspoon ground black pepper

Instructions:

  1. In a bowl, combine sliced steak with soy sauce, cornstarch, sesame oil, and pepper. Marinate for at least 15 minutes (or up to 30 minutes in the fridge).
  2. Whisk together beef broth, soy sauce, oyster sauce (if using), brown sugar, cornstarch, rice vinegar, sesame oil, and pepper in a small bowl. Set aside.
  3. Heat vegetable oil in a large skillet or wok over medium-high heat. Add onion and cook until softened, about 3 minutes. Add bell peppers and cook until slightly tender, about 5 minutes. Add garlic and ginger, cook for 1 minute more, until fragrant. Remove vegetables from the skillet and set aside.
  4. Add another tablespoon of vegetable oil to the skillet. Add marinated steak in a single layer (cook in batches if necessary to avoid overcrowding the pan). Cook quickly, stirring constantly, until browned and cooked through, about 3-4 minutes. Remove steak from the skillet and set aside.
  5. Pour the sauce into the skillet and bring to a simmer, stirring constantly. Cook until the sauce thickens slightly, about 1-2 minutes.
  6. Return the steak and vegetables to the skillet. Toss to coat with the sauce. Cook for 1-2 minutes more, until heated through.
  7. Serve immediately over steamed rice. Garnish with sesame seeds or chopped green onions (spring onions) if desired.