Peruvian Steak Stir-Fry with Tomatoes and Fries Recipe

Peruvian steak stir-fry, inspired by lomo saltado, brings seared beef together with tomato, red onion, soy sauce, and tangy vinegar, then serves it with crisp fries. The dish reflects Peru’s Chinese-Peruvian chifa cooking, and home versions vary; this practical take keeps the savory, bright flavors while making the fries in the oven.

Ingredients

1 lb (450 g) flank steak or sirloin, trimmed
1 lb (450 g) russet potatoes, scrubbed
3 tbsp (45 ml) neutral oil, divided
1 medium red onion (about 170 g), cut into thick wedges
2 medium Roma tomatoes (about 250 g), cut into wedges
2 garlic cloves (about 6 g), finely chopped
1 tbsp (15 g) ají amarillo paste, optional
2 tbsp (30 ml) regular soy sauce
1 tbsp (15 ml) red wine vinegar
2 tbsp (30 ml) water or low-sodium beef broth
½ tsp (1 g) ground cumin
½ tsp (3 g) fine salt, plus more to taste
¼ tsp (0.5 g) freshly ground black pepper
2 tbsp (8 g) chopped cilantro leaves and tender stems
1 lime (about 60 g), cut into wedges, for serving

Instructions

Prepare the ingredients. Pat the steak dry and slice it across the grain into strips about ½ inch (1.25 cm) thick and 2 inches (5 cm) long. Keeping the pieces a little thicker than typical stir-fry strips makes them easier to check with a thermometer. Cut the potatoes lengthwise into fries about ⅓ inch (8 mm) thick. Slice the onion into wedges, cut the tomatoes into wedges, and chop the garlic. Measure the sauce ingredients so they are ready to add quickly. This prep takes about 20 minutes.
Bake the fries. Heat the oven to 450°F (230°C). Toss the potato fries with 1½ tablespoons (22 ml) of the oil and spread them out on a large rimmed baking sheet in one layer. Bake for 25 minutes, turning them after about 13 minutes, until browned and tender inside. If your oven runs cool or the fries are thicker, give them a few extra minutes; don’t crowd them, or they will steam rather than crisp. Season with a pinch of salt when they come out. Keep the fries on the tray while you make the beef.
Mix the sauce and season the steak. While the fries bake, stir together the soy sauce, vinegar, water or broth, cumin, ají amarillo paste if using, and black pepper in a small bowl. Sprinkle the steak with the measured salt. If the steak has released moisture, pat it dry again before it hits the pan; a dry surface browns more readily.
Sear the steak in batches. Heat a large, heavy skillet or wok over high heat until hot. Add 1 tablespoon (15 ml) of the remaining oil and swirl to coat. Add half the steak in a single layer, leaving space between pieces. Sear for about 1½ minutes per side, turning once, then transfer it to a clean plate. Repeat with the remaining oil and steak. Avoid piling all the meat into the pan at once, since the temperature can drop and the beef may turn pale and release liquid instead of browning.
Cook the vegetables and sauce. Add the onion to the hot pan and stir-fry for about 2 minutes, until it starts to soften but still has some bite. Add the garlic and cook for 20 to 30 seconds, stirring so it does not burn. Add the tomato wedges and cook for about 1 minute, just until their edges begin to soften. Pour in the sauce and let it bubble for 30 to 60 seconds, scraping up browned bits from the pan.
Finish and check the beef. Return the steak and any juices on the plate to the pan. Toss briefly to coat, then check the thickest steak piece with a food thermometer. USDA FSIS lists 145°F (63°C), followed by a 3-minute rest, as the safe minimum for whole cuts of beef. Transfer the beef to a clean plate and let it rest for 3 minutes; keep the hot vegetables and sauce in the pan. If any piece has not reached 145°F (63°C), return it to the pan and cook, checking again. The thin strips cook quickly, so avoid leaving them in the pan longer than needed.
Combine and serve. Add the hot fries to the pan just before serving and toss gently so some catch the sauce while others stay crisp. Fold in the cilantro, taste the sauce, and adjust the salt if needed. Serve at once with lime wedges. For the best contrast in texture, you can also pile the fries onto plates and spoon the steak and vegetables over them instead of tossing everything together.

Tips

Slice across the grain. Look for the long muscle fibers in the steak and cut across them, not along them. Shorter fibers make each bite easier to chew. If the steak is difficult to slice cleanly, chill it in the freezer for 15 to 20 minutes first; it should be firm, not frozen.
Use a wide, very hot pan. A large skillet gives moisture room to evaporate and helps the steak brown. Cook in batches even if that takes an extra minute. A smaller pan or an overloaded one tends to steam the meat and soften the vegetables.
Keep the tomatoes and onion lively. The vegetables should soften at the edges without collapsing into a fully cooked sauce. Cut them into substantial wedges and add them after the steak has been seared. If your tomatoes are especially juicy, use a little less broth or water so the sauce stays glossy rather than watery.
Adjust the heat thoughtfully. Ají amarillo gives the dish a fruity, gentle chile flavor. If you cannot find the paste, omit it or use 1 tablespoon (15 g) finely chopped yellow bell pepper for color and sweetness; bell pepper is not hot and will make the result milder. A small pinch of cayenne can add heat, but it will not reproduce ají amarillo’s particular flavor.

Serving Suggestions

Serve the stir-fry immediately, while the beef is warm and the fries are crisp. A common way to enjoy lomo saltado is with both fries and rice, so offer steamed white rice alongside if you want a more filling meal. The rice also catches the savory, vinegar-bright pan sauce. If you prefer a lighter plate, serve the beef and vegetables over a modest portion of fries with lime wedges and a simple green salad.

Keep the lime on the table rather than squeezing it over the whole pan. A little fresh juice on each serving brightens the rich beef and balances the salty soy sauce. For a casual family-style meal, bring the pan to the table and let everyone add fries to their own plate; that helps any extra fries stay crisp. A mild, crunchy salad with lettuce or cucumber is a good contrast, while strongly dressed sides can compete with the tangy sauce.

Variations

Use another cut of beef: Skirt steak works well if it is trimmed and sliced across the grain. Sirloin is a convenient, leaner option. Avoid very thin pre-cut beef if you want to check the safe temperature reliably, and expect thicker pieces to need more time in the pan.

Make it spicier: Keep the ají amarillo and add a thinly sliced fresh chile, adjusting the amount to suit your preference. For less heat, leave out the paste and serve chile separately. Ají amarillo’s fruity flavor is distinct, so a generic hot sauce changes the taste as well as the heat.

Use a different potato method: Frozen oven fries can replace the homemade fries. Bake them according to the package directions and keep them separate until serving. They are convenient, though their seasoning and texture may differ; check for added salt before seasoning the beef and sauce.

Make it gluten-free: Choose a soy sauce labeled gluten-free, such as tamari, and check the labels on any broth and ají amarillo paste. The sauce will remain savory, though tamari can taste a little richer, so taste before adding extra salt.

Storage and Reheating

For food safety, refrigerate leftovers within 2 hours of cooking, storing them in a covered, shallow container. The cooked steak and vegetables keep for 3 to 4 days in the refrigerator. Store leftover fries separately if possible; they soften when held in the sauce. If the fries have already been mixed in, the dish is still fine to keep, but their texture will be softer after chilling.

Reheat only the portion you plan to eat. Warm the beef and vegetables in a skillet over medium heat with a splash of water, stirring until steaming hot throughout; add the fries near the end if they are stored together. For food safety, USDA FSIS advises reheating leftovers to 165°F (74°C), checked with a food thermometer. An oven or air fryer can help crisp separately stored fries again, but do not leave the beef in heat longer than necessary or it may become tough. Freeze leftovers in a sealed container for up to 2 months for best quality; thaw in the refrigerator before reheating. The fries will lose crispness after freezing.

Frequently Asked Questions

Is this the same as lomo saltado? It is a home-style steak stir-fry inspired by lomo saltado, a well-known Peruvian dish associated with chifa, Peru’s Chinese-Peruvian cuisine. The combination of beef, tomato, onion, soy sauce, vinegar, and fries is characteristic, but family and restaurant versions vary in seasoning, cut of beef, and how the fries are served. This version bakes the fries rather than frying them in oil.

Can I cook the fries in an air fryer? Yes. Cook the cut potatoes in batches at about 400°F (205°C), following your air fryer’s guidance and shaking the basket occasionally. Timing varies by appliance and by how full the basket is, so cook until the fries are browned and tender. Keep them warm and separate, then toss them with the beef just before serving.

Why is my steak tough? The most common causes are cutting with the grain, using a pan that is not hot enough, or leaving the meat in the pan too long. Slice across the grain, pat the meat dry, and sear in uncrowded batches. Check the thickest piece with a thermometer and take the beef out to rest as soon as it reaches the safe temperature; continuing to cook it in the sauce can make the strips firmer.

Can I prepare any of this ahead? You can cut the potatoes, onion, and tomatoes and store them covered in the refrigerator for up to a day. Keep the cut potatoes submerged in cold water to prevent browning, then drain and dry them very thoroughly before tossing with oil. You can also mix the sauce ahead. For the best texture, slice and cook the steak shortly before serving and bake the fries just before the final stir-fry.

What can I use instead of red wine vinegar? Distilled white vinegar or rice vinegar can work in the same amount. White vinegar tastes sharper, while rice vinegar is gentler and may make the sauce a little less tangy. Apple cider vinegar is another option, with a mild fruity note. Add the replacement as written, taste the finished sauce, and adjust with a small splash more only if it needs brightness.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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