Begin by thinly slicing the sirloin beef against the grain, then place it in a bowl. Pour soy sauce and apple cider vinegar over the beef, ensuring all slices are coated. Allow it to marinate for 15–20 minutes at room temperature.

While the beef marinates, chop the red onion, plum tomatoes, and scallions into bite-sized pieces.

Place a wok or a cast-iron skillet over high heat and drizzle in a tablespoon of oil, allowing it to shimmer for about 1 minute.

Add the marinated beef to the hot skillet in batches, searing each batch for 2–3 minutes until it turns a rich brown color.

In the same skillet, add the chopped red onion, tomatoes, and scallions. Stir-fry them for 1–2 minutes until the onions become translucent.

Return the seared beef to the skillet and add the aji amarillo paste, minced garlic, ginger, and optional spices. Stir everything together for an additional 1–2 minutes.

Immediately serve your Lomo Saltado over jasmine rice, accompanied by French fries. Garnish with fresh herbs.