Lomo Saltado Vietnamese-Style Stir-Fry

Vietnamese-style lomo saltado is a quick beef stir-fry inspired by Peru’s lomo saltado, pairing seared beef with tomatoes, red onion, soy-seasoned pan juices and fries. This home-cook version uses familiar Vietnamese pantry flavors, including fish sauce and lime, and is served with rice and crisp potatoes for a savory, tangy, satisfying meal.

Ingredients

1 lb (450 g) flank steak or sirloin, trimmed and cut across the grain into strips about ¼ inch (6 mm) thick
1 lb (450 g) russet potatoes, peeled or scrubbed and cut into ½-inch (1.3 cm) fries
3 tablespoons (45 ml) neutral cooking oil, divided
1 teaspoon (5 g) fine salt, divided
½ teaspoon freshly ground black pepper, divided
1 medium red onion, about 8 oz (225 g), cut into thick wedges
2 medium ripe tomatoes, about 10 oz (280 g), cut into wedges
2 garlic cloves, finely chopped
2 tablespoons (30 ml) soy sauce
1 tablespoon (15 ml) fish sauce
1 tablespoon (15 ml) fresh lime juice, plus lime wedges for serving
1 teaspoon (5 g) sugar
2 scallions, thinly sliced
¼ cup loosely packed cilantro leaves (about 10 g), roughly chopped
4 cups cooked jasmine rice (about 740 g), for serving

Instructions

Prepare the potatoes and beef. Heat the oven to 425°F (220°C). Pat the beef dry and season it with ½ teaspoon salt and ¼ teaspoon pepper. In a small bowl, stir together the soy sauce, fish sauce, lime juice and sugar. Keep the beef and sauce chilled while you prepare the fries if you need more than a few minutes.
Roast the fries. Toss the potato sticks with 1 tablespoon (15 ml) oil and the remaining ½ teaspoon salt. Spread them in a single layer on a rimmed baking sheet, leaving space between pieces. Roast for 20–25 minutes, turning once, until browned and tender. The fries can cook while you prepare the stir-fry; remove them from the oven when ready.
Sear the beef. Heat a large wok or heavy skillet over high heat until very hot. Add 1 tablespoon (15 ml) oil, then arrange the beef in a single layer; work in two batches if the pan is crowded. Let it sear briefly, then toss and cook just until browned. Check the thickest pieces with a food thermometer: USDA FSIS safe minimum for whole cuts of beef is 145°F (63°C), followed by a 3-minute rest. Transfer the beef to a clean plate and let it rest for at least 3 minutes.
Stir-fry the vegetables. Add the final 1 tablespoon (15 ml) oil to the pan. Add the onion and cook for about 2 minutes, tossing, until it begins to soften but still has some bite. Add the garlic and cook for 20 seconds, then add the tomatoes and the remaining ¼ teaspoon pepper. Stir-fry for 1–2 minutes, just until the tomatoes begin to release their juices.
Finish the stir-fry. Return the rested beef and any juices on the plate to the pan. Pour in the sauce mixture and toss over high heat for about 1 minute, until everything is coated and hot. Taste and adjust with a little more lime or soy sauce if needed. Fold in the scallions and cilantro.
Serve promptly. Divide the hot rice among four plates or shallow bowls. Add the beef and vegetables, then serve the fries alongside or on top just before eating so they retain their crispness. Offer lime wedges at the table.

Tips

Slice across the grain. Look for the direction of the muscle fibers and cut across them; thin slices cook quickly and are easier to chew. Partially freezing the beef for 15–20 minutes can make it easier to slice, but add that time to the total if you use this option.
Keep the pan hot and uncrowded. Crowding traps steam and can make the beef gray rather than seared. Cook in batches, letting the pan heat back up between them.
Use Vietnamese fish sauce thoughtfully. It brings salty, fermented depth. If unavailable, use an equal amount of soy sauce; the result will be less aromatic and slightly less complex. Taste before adding extra salt.
Protect the fries’ texture. Roast them on a spacious, preheated pan if possible, and keep them separate from the saucy stir-fry until serving. For a crispier finish, turn the fries once and avoid lining them up in a pile.

Serving Suggestions

Jasmine rice makes a simple base for catching the beef juices. Put the fries on the side for the best contrast, or tuck them beside the rice and add the stir-fry on top at the last moment. A cucumber salad dressed with rice vinegar, lime and a pinch of sugar adds a cool, crunchy counterpoint. Extra lime wedges and sliced fresh chile are welcome at the table, especially for diners who like more brightness or heat.

Variations

For a milder, less fish-forward sauce, replace the fish sauce with soy sauce and add a small squeeze of lime at the end. If flank steak or sirloin is unavailable, use another tender, boneless beef cut and slice it thinly across the grain. Chicken can be substituted, but cook it to 165°F (74°C), the USDA FSIS safe minimum internal temperature for poultry, checking the thickest pieces with a thermometer. For a vegetarian version, use firm tofu, pressed and cut into cubes; sear it until golden before stir-frying the vegetables. Sweet potato fries also work, though they cook and brown differently, so check them early.

Storage and Reheating

Refrigerate leftovers within 2 hours, storing the beef and vegetables, rice and fries separately in airtight containers. Cooked beef and vegetables and cooked rice keep for 3–4 days in the refrigerator at 40°F (4°C) or below; fries are best within 1–2 days, though they will soften. Reheat leftovers to 165°F (74°C), checking with a food thermometer. Warm the beef and vegetables in a skillet with a splash of water, and reheat rice separately with a little water, covered. Re-crisp fries in a 400°F (205°C) oven or air fryer until hot; avoid storing fries mixed into the sauce.

Frequently Asked Questions

Is Vietnamese lomo saltado a traditional Vietnamese dish?
This is a Vietnamese-inspired adaptation of lomo saltado, a Peruvian stir-fry commonly made with beef, onion, tomato and fries. The fish sauce and lime in this recipe bring Vietnamese pantry flavors; recipes and adaptations vary.

Can I make the fries in an air fryer?
Yes. Toss them with the oil and salt and air-fry in a single layer at about 400°F (205°C), shaking or turning as needed, until crisp and tender. Timing varies by machine and batch size, so begin checking after 15 minutes.

Can I prepare any parts ahead?
You can cut the beef and vegetables and mix the sauce a few hours ahead; cover and refrigerate them separately. Cut potatoes are best cooked soon after cutting, or kept submerged in cold water in the refrigerator, then drained and thoroughly dried before roasting. Cook rice fresh or handle previously cooked rice safely: chill it promptly and reheat it thoroughly.

Why is my beef tough?
Common causes include slicing with the grain, using a crowded or insufficiently hot pan, or cooking the strips too long. Slice across the grain, sear in batches, and use a thermometer to check the safe temperature without leaving the beef in the pan longer than necessary.

Can I make this without fish sauce?
Yes. Replace it with the same amount of soy sauce. The sauce will still be savory, but it will lack some of fish sauce’s distinctive fermented aroma, so finish with lime to balance the flavors.

How do I keep the potatoes crisp?
Roast them in a single layer with space around each piece, and serve them separate from the sauce until the meal is plated. If they soften in storage, reheat them in a hot oven or air fryer rather than the microwave.

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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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