For the stir-fry:

500g (1 lb) beef sirloin or rump steak, cut into strips

1 large red onion, cut into thick slices

2 tomatoes, cut into wedges

1 yellow chili pepper (aji amarillo), sliced

2 cloves garlic, minced

2 tbsp soy sauce

1 tbsp red wine vinegar or white vinegar

1 tbsp oyster sauce (optional)

Salt & black pepper to taste

Fresh cilantro, chopped

2 tbsp vegetable oil

For serving:

Cooked white rice

French fries (homemade or frozen)