- 1 lb (450g) flank steak or sirloin, thinly sliced against the grain
- 1 tablespoon low-sodium soy sauce
- 1 teaspoon cornstarch
- 1 teaspoon sesame oil
- ½ teaspoon baking soda (for extra tender beef)
- 1 teaspoon rice vinegar
For the Stir-Fry:
- 2 tablespoons vegetable oil (or peanut oil)
- 1 large onion, sliced into thin strips
- 1 red bell pepper, sliced
- 1 green bell pepper, sliced
- 2 cloves garlic, minced
- 1 teaspoon ginger, grated
For the Sauce:
- ¼ cup low-sodium soy sauce
- 2 tablespoons oyster sauce (or hoisin sauce for a sweeter version)
- 1 tablespoon cornstarch mixed with 2 tablespoons water (slurry)
- 1 teaspoon sugar (or a sugar substitute)
- ½ teaspoon black pepper (freshly ground for best flavor)
- ½ teaspoon crushed red pepper flakes (optional for heat)
- ¼ cup beef broth or water