Prepare the fries: Preheat your oven to 400°F (200°C). Toss the cut potatoes with 1 tablespoon of vegetable oil and a pinch of salt on a baking sheet. Spread them in a single layer and bake for 20-25 minutes, or until golden brown and crispy, flipping halfway through. Alternatively, you can fry them in oil until golden.

Marinate the beef: In a medium bowl, combine the thinly sliced beef with soy sauce, red wine vinegar, cumin, and black pepper. Toss to coat evenly and let it marinate for at least 15-20 minutes at room temperature while you prepare the vegetables.

Sear the beef: Heat the remaining 1 tablespoon of vegetable oil in a large wok or heavy-bottomed skillet over high heat until shimmering. Add the marinated beef in a single layer (work in batches if necessary to avoid overcrowding). Sear for 1-2 minutes per side until browned but still slightly pink in the center. Remove the beef from the wok and set aside.

Stir-fry the vegetables: Add the red onion wedges and tomato wedges to the hot wok. Stir-fry for 2-3 minutes until the onions are slightly softened and the tomatoes are just beginning to break down. Add the sliced ají amarillo peppers (if using) and minced garlic, and stir-fry for another minute until fragrant.

Combine and finish: Return the seared beef to the wok with the vegetables. Add the chopped cilantro and parsley. Toss everything together quickly for about 30 seconds to heat through and combine the flavors.

Serve: Immediately spoon the Lomo Saltado mixture over or alongside the cooked white rice. Top generously with the crispy baked fries and garnish with extra fresh cilantro and parsley. Serve hot and enjoy the incredible fusion of flavors!