Fry the potatoes. Heat 2 inches of oil to 350°F. Fry potato strips in batches until golden and crispy, 5–6 minutes per batch. Drain on paper towels, salt immediately. Set aside.

Sear the beef — this is the whole game. Get a wok or cast iron screaming hot. Season beef with salt and pepper. Cook in small batches (don't crowd the pan or you'll get grey, sad beef). Sear 60–90 seconds per batch until deeply browned. Remove and set aside.

Stir-fry the aromatics. Same pan, still ripping hot. Add a splash of oil, then onion wedges. Toss for 30 seconds — you want them softened but still with bite. Add garlic and aji amarillo, stir 15 seconds until fragrant.

Build the sauce. Add tomato wedges, soy sauce, vinegar, and oyster sauce. If using pisco, add it now and let it flame off. Toss for 30 seconds — tomatoes should soften but hold their shape.

Return the beef to the pan. Toss everything together for 15–20 seconds. The sauce should coat everything in a glossy glaze. Don't overcook — the beef should still be medium.

Plate it up. Pile the stir-fry on one side, fries on the other, rice alongside. Shower with cilantro. Some people toss half the fries into the stir-fry (Gaston Acurio's move) — worth trying.