This Cambodian-style stir-fry is inspired by lok lak, a popular Cambodian beef dish served with fresh vegetables and a tangy black-pepper-and-lime dip. Recipes vary by cook; this version pairs quickly seared beef with a savory sauce, crisp cucumber and tomato, and rice for a practical weeknight meal.
Ingredients
- 1 lb (450 g) beef sirloin or flank steak, trimmed and cut across the grain into thin strips
- 1 tbsp (15 ml) soy sauce
- 1 tbsp (15 ml) oyster sauce
- 2 tsp (10 ml) fish sauce
- 1 tsp (4 g) light brown sugar
- 3 garlic cloves (about 9 g), finely minced
- 1 tsp (2 g) freshly ground black pepper, divided
- 1 tbsp (15 ml) neutral oil, such as canola or sunflower oil
- 1 medium yellow onion (about 150 g), thinly sliced
- 2 medium tomatoes (about 300 g), cut into wedges
- 1 small cucumber (about 200 g), thinly sliced
- 4 cups (about 240 g) torn lettuce leaves
- 2 tbsp (30 ml) fresh lime juice, divided
- 1 tbsp (15 ml) water
- 2 scallions (about 30 g), thinly sliced
- ¼ cup (10 g) loosely packed cilantro leaves, optional
- 4 cups (about 600 g) cooked jasmine rice, warm, for serving
Instructions
- Prepare the beef and vegetables. Pat the beef dry with paper towels, then slice it across the grain into strips about ¼ inch (6 mm) thick. Cutting across the visible muscle fibers helps keep the cooked strips tender. Slice the onion, tomatoes, cucumber, lettuce, and scallions, and arrange the cucumber, lettuce, and tomatoes on a serving platter or individual plates.
- Mix the seasoning. In a small bowl, stir together the soy sauce, oyster sauce, fish sauce, brown sugar, garlic, ½ teaspoon of the black pepper, and the water. Add the beef and toss until coated. It does not need a long marinade; while you prepare the lime dip and heat the pan, the seasoning will cling to the strips.
- Make the pepper-lime dip. In another small bowl, combine the remaining ½ teaspoon black pepper with 1 tablespoon (15 ml) lime juice. Taste it. For a sharper, more peppery dip, add a little more lime or pepper; for a gentler flavor, add 1 teaspoon water. Set it beside the vegetable platter.
- Heat the pan. Set a large wok or heavy skillet over high heat until very hot, about 2 minutes. Add the oil and swirl to coat the bottom. If your pan is small, plan to cook the beef in two batches; crowding it makes the meat release liquid and steam instead of browning.
- Sear the beef. Lift the beef from the seasoning bowl, letting excess sauce drip back into the bowl. Add half the beef in a single layer and cook without moving it for about 1 minute, then stir-fry for another 1 to 2 minutes, until browned on the outside. Transfer it to a clean plate and repeat with the remaining beef. If the pan looks dry between batches, add a teaspoon of oil.
- Cook the onion and finish the sauce. Add the sliced onion to the hot pan and stir-fry for about 1 minute, just until it begins to soften but still has some bite. Pour in the reserved seasoning mixture and let it bubble for 30 seconds, scraping up browned bits from the pan. Return the beef and any juices to the pan, then toss for about 1 minute to coat.
- Check the beef and rest it. Use a food thermometer to check the thickest pieces: whole cuts of beef must reach the USDA FSIS safe minimum internal temperature of 145°F (63°C), followed by a 3-minute rest. If the strips have not reached that temperature, continue cooking briefly and check again. Transfer the cooked beef to a clean platter and let it rest for 3 minutes.
- Serve. Spoon the beef and onions over the lettuce and arrange the tomatoes and cucumber around it. Scatter on the scallions and cilantro, if using, and drizzle the remaining 1 tablespoon (15 ml) lime juice over the vegetables. Serve with warm rice and the pepper-lime dip on the side.
Tips
- Choose the right cut and slice it well. Sirloin is easy to slice and cooks quickly; flank steak also works, but it is especially important to cut it across the grain. Partially chilling the beef for 15 to 20 minutes can make thin, even slices easier, though that optional chill adds time to the recipe.
- Adjust the salty ingredients thoughtfully. Fish sauce, soy sauce, and oyster sauce all contribute salt, and their brands differ in intensity. If you are sensitive to saltiness, start with 1 teaspoon fish sauce and add more after tasting the pan sauce. Do not replace all three with extra soy sauce; the result will lose the rounded, savory character of the original combination.
- Use a hot pan and work in batches. Give the pan time to heat, and leave space around the beef strips. A crowded pan traps steam, so the meat turns gray and may become watery. Keep each batch moving only after its first side has had a chance to brown.
- Keep the vegetables crisp. This dish is meant to contrast hot, savory beef with cool, fresh vegetables. Add the lime juice shortly before serving, rather than dressing the platter far in advance, so the lettuce and cucumber stay crisp.
Serving Suggestions
Serve the beef hot, directly over a bed of warm jasmine rice, with the lettuce, cucumber, and tomato arranged alongside or underneath. The vegetables are more than decoration: their cool crunch balances the rich, salty-sweet beef and gives the plate a fresh finish. Put the pepper-lime dip on the table so each person can spoon it over the beef or dip a bite as they eat.
If you want a fuller meal, add a simple bowl of clear vegetable soup or a plate of steamed greens. Keep other sides lightly seasoned, since the stir-fry and dipping sauce already bring plenty of savory flavor. A little extra lime at the table is useful for anyone who likes more acidity, while extra black pepper lets diners make the dip bolder without changing the whole pan.
Variations
Use chicken or pork. Thinly sliced boneless chicken thighs or pork loin can stand in for beef. Cook chicken until it reaches 165°F (74°C), or pork whole cuts until they reach 145°F (63°C) and rest for 3 minutes, checking with a food thermometer. Their texture and flavor differ from beef, but the same garlic, fish sauce, and pepper-lime combination works well.
Make it without oyster sauce. For a shellfish-free version, replace the oyster sauce with 1 tablespoon (15 ml) additional soy sauce and 1 teaspoon (5 ml) water. The sauce will be saltier and less rounded, so taste before adding extra fish sauce. A vegetarian mushroom-based stir-fry sauce can also work; check its label, since ingredients and salt levels vary.
Add aromatic herbs or heat. A small, finely minced stalk of lemongrass can be cooked with the onion for a more fragrant variation, though it is not required for this lok lak-inspired version. For heat, add a sliced bird’s-eye chile to the pepper-lime dip or stir a pinch of chile flakes into the pan. Start modestly so the lime and black pepper remain noticeable.
Swap the rice or vegetables. Serve with steamed brown rice or rice noodles if preferred. Thinly sliced bell pepper can supplement the cucumber and tomato, but it is best cooked briefly with the onion rather than left raw on the platter. Keeping at least some cool, fresh vegetables preserves the contrast that makes this style of serving satisfying.
Storage and Reheating
Refrigerate leftover beef and vegetables within 2 hours of cooking, preferably in shallow, airtight containers. The cooked beef keeps for 3 to 4 days in the refrigerator at 40°F (4°C) or colder. Store the rice separately from the vegetables when possible; lettuce and cucumber soften after contact with warm sauce, so keep any unused fresh vegetables apart and assemble them when serving.
Reheat the beef and onions in a skillet over medium heat with a splash of water, stirring until steaming hot, or microwave them in a covered microwave-safe dish, stirring halfway through. Leftovers should reach 165°F (74°C), measured with a food thermometer. Reheat only the portion you plan to eat, since repeated heating can make the beef dry. The pepper-lime dip is best made fresh, but a covered portion can be refrigerated for up to 2 days; stir it before serving. Freeze leftover cooked beef, without the fresh vegetables, for up to 2 months for best quality, then thaw in the refrigerator and reheat to 165°F (74°C).
Frequently Asked Questions
Is this the same as Cambodian lok lak? It is a home-cook-friendly version inspired by lok lak, a well-known Cambodian beef dish commonly served with vegetables and a lime-and-black-pepper sauce. Ingredients and presentation vary between recipes and households. This version uses a quick soy, oyster, and fish sauce seasoning, and serves the beef with crisp vegetables and rice.
Can I prepare the beef ahead? You can slice the beef and mix the seasoning up to a day ahead, keeping them covered separately in the refrigerator. For the best texture, toss the beef with the sauce shortly before cooking rather than leaving it in a salty marinade for many hours. Slice the vegetables ahead too, but store the lettuce, cucumber, and tomatoes separately and assemble the platter near serving time.
What can I use instead of fish sauce? If you need to avoid fish sauce, use additional soy sauce or a vegetarian fish-style seasoning, adding it gradually and tasting as you go. Soy sauce gives a more direct salty flavor and lacks fish sauce’s distinctive savory depth, so the finished stir-fry will taste a little different. For a fully vegetarian meal, replace the beef with firm tofu and use a vegetarian oyster-style sauce.
How do I keep the beef tender? Start with a tender cut, slice across the grain, dry the surface, and cook in a very hot pan without overcrowding. Thin strips need only a short time, but they still must reach the safe temperature specified in the instructions. Letting the cooked beef rest for 3 minutes helps keep the juices in the meat; avoid simmering it in the sauce for a long time.
Can I make this recipe without a wok? Yes. A wide, heavy skillet works well if it gets hot and has enough surface area for the beef to brown. Cook in batches when needed, and do not pour the full bowl of marinade into the pan at the beginning, since excess liquid can prevent browning. Add the reserved seasoning after the onion has had a brief turn in the pan.
Is the pepper-lime dip supposed to be very spicy? It is usually sharp and peppery rather than chile-hot. Fresh lime juice and ground black pepper make a punchy dip, but you can reduce the pepper or add a teaspoon of water to soften it. Chile is an optional variation, not essential to the dip, and can be served separately for guests who want heat.
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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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