1 lb flank steak, thinly sliced against the grain
2 bell peppers (red and green), sliced
1 large onion, sliced
3 tbsp soy sauce (plus 2 tbsp for marinade)
2 tbsp oyster sauce
2 tbsp cornstarch
½ cup beef broth
1 tsp rice vinegar
2 garlic cloves, minced
1 tsp fresh ginger, minced
3 tbsp oil for stir-frying
Marinate beef with soy sauce, cornstarch, and rice vinegar for 15 minutes.
Mix sauce ingredients in a bowl.
Heat wok, sear beef for 1–2 minutes per side. Remove.
Stir fry peppers and onions 3–4 minutes. Add garlic and ginger.
Return beef, pour sauce, and cook until thickened.
Serve hot over rice or noodles.
Slice beef thinly for tenderness.
Double sauce if you like extra for rice.
Add chili flakes for heat.