Begin by marinating the beef. In a large bowl, combine the beef strips with soy sauce, red wine vinegar, ground cumin, and minced garlic. Toss well to coat evenly. Cover the bowl and refrigerate for at least 20 minutes to allow the flavours to penetrate the meat.

While the beef marinates, prepare your vegetables. Slice the red onion and tomatoes into wedges, ensuring the pieces are large enough to hold their shape during cooking. If using yellow chili pepper, julienne it finely. Keep all vegetables ready in separate bowls.

Heat a large wok or heavy bottomed skillet over high heat. Add 1 tablespoon of vegetable oil. Once the oil is shimmering, remove the beef from the marinade and stir fry it in batches to avoid overcrowding the pan. Cook for 2–3 minutes until the beef is seared and browned. Transfer to a plate and set aside.

In the same wok, add another tablespoon of oil and heat over medium-high. Toss in the red onion wedges and stir fry for about 2 minutes, just until slightly softened but still crisp. Add the tomatoes and chili pepper, stirring gently to avoid breaking the tomato wedges.

Return the beef to the wok and stir to combine. Pour in 1 tablespoon each of soy sauce and red wine vinegar. Stir fry for another 2 minutes, allowing the ingredients to meld together. Season with salt and pepper to taste.

While the stir fry is finishing, prepare the French fries. If using store bought fries, heat them according to package instructions until crispy. For homemade fries, deep fry or bake them until golden. Ensure they’re hot and ready to serve.

To assemble, layer the crispy French fries into the wok with the beef and vegetables. Toss gently to coat the fries in the sauce without making them soggy. Cook for 1 minute to warm everything through.

Serve the Lomo Saltado immediately with a side of steamed white rice. Garnish with chopped cilantro for a fresh burst of flavour. For an authentic touch, pair the dish with aji sauce or lime wedges. Ensure all components are hot for the best dining experience.