Mongolian beef is the kind of takeout order that seems complicated to recreate at home — tender strips of beef in a glossy, sweet-savory sauce. This crockpot version proves it isn’t. Everything goes into the slow cooker, and in about three hours you’ve got velvety, tender beef coated in a rich, well-balanced soy-garlic sauce that tastes just as good as anything from your favorite takeout menu (or a certain well-known restaurant chain’s version).
If you’ve never used a slow cooker for a stir-fry-style dish before, this is a good place to start. No one has to stand over a hot wok—the crockpot handles the cooking that makes the beef tender, and a quick cornstarch slurry at the end thickens the sauce into that classic glossy coating. The key is not overcooking: because flank steak and sirloin are lean cuts with little internal fat, a shorter, carefully timed cook keeps the meat tender instead of drying it out and turning it stringy.
It’s easy enough for a weeknight and hearty enough to serve for a family dinner or holiday meal alongside rice and steamed vegetables.
Why This Crockpot Mongolian Beef Works
- Takeout flavor, home kitchen effort. A simple soy sauce, brown sugar, garlic, and ginger base delivers that sweet-savory Mongolian beef flavor without a special trip to the Asian grocery store.
- Velvety, tender beef. A shorter, optimized cook time keeps lean cuts like flank steak or sirloin from drying out, so the beef stays tender rather than chewy.
- Balanced, not cloying. A splash of rice vinegar and a lighter touch of brown sugar cut through the soy sauce so it tastes rich and savory instead of one-note sweet.
- Hands-off cooking. Once it’s in the crockpot, you don’t need to stir or babysit until the very end.
- Family-friendly. Mild enough for kids, with heat you can dial up separately for the adults.
- Easy to scale. Doubles well for a crowd or a holiday spread, with little extra effort.
Crockpot Mongolian Beef
Tender, velvety strips of beef slow-cooked in a balanced sweet-and-savory soy-garlic sauce, finished with a quick cornstarch slurry for a glossy, takeout-style coating.
Ingredients
- 1½ lbs flank steak or top sirloin, sliced very thin against the grain into ¼-inch strips
- ¼ cup cornstarch, for coating the beef
- 1 tablespoon neutral cooking oil (like avocado or canola)
- ½ cup low-sodium soy sauce
- ½ cup water or low-sodium beef broth
- ⅓ cup packed dark brown sugar
- 1 tablespoon rice vinegar
- 4 garlic cloves, minced
- 1 tablespoon fresh ginger, grated
- 1 teaspoon toasted sesame oil
- ¼–½ teaspoon red pepper flakes, optional, for heat
- 2 tablespoons cornstarch mixed with 2 tablespoons cold water, for the finishing slurry
- 4 green onions, sliced on a diagonal, whites and greens separated
- 1 tablespoon toasted sesame seeds
- Cooked white or brown rice, for serving
Instructions
- Slice the steak very thin, against the grain, into ¼-inch strips. Toss the strips with ¼ cup cornstarch in a large bowl until evenly coated. This helps the sauce cling to the meat and gives the finished dish its classic velvety texture.
- In a medium bowl, whisk together the soy sauce, water or beef broth, brown sugar, rice vinegar, garlic, ginger, sesame oil, and red pepper flakes (if using) until the sugar dissolves.
- Place the cornstarch-coated beef into a 6-quart slow cooker. Pour the sauce mixture over, then add the white parts of the sliced green onions. Stir gently to combine.
- Cover and cook on LOW for 3 hours, or on HIGH for 1.5 to 2 hours, until the beef is tender and cooked through. Don't overcook—because these are lean cuts, extra time in the slow cooker will dry the meat out rather than make it more tender.
- In a small bowl, whisk the remaining 2 tablespoons cornstarch with 2 tablespoons cold water until smooth. Stir this slurry into the slow cooker. Cover and cook on HIGH for another 15 minutes, until the sauce has thickened and turned glossy.
- Stir in half of the sliced green onion tops.
- Serve hot over rice, garnished with the remaining green onions and toasted sesame seeds.
Notes
Instant Pot Method
Toss the beef with cornstarch, then add it to the Instant Pot with the sauce ingredients (including the green onion whites), as directed above. Seal the lid and cook on high pressure for 8–10 minutes, then let the pressure release naturally for 10 minutes before quick-releasing the rest. Switch to the sauté function, stir in the cornstarch slurry, and cook for 3–5 minutes, stirring, until thickened. Finish with the green onion tops and sesame seeds as directed.
Tips for the Best Mongolian Beef
- Slice the beef very thin and against the grain. This is what keeps the strips tender rather than chewy, especially with a shorter cook time.
- Don’t overcook lean cuts. Flank steak and sirloin have little internal fat, so beyond a certain point, more time in the slow cooker works against you — the muscle fibers tighten and squeeze out moisture instead of breaking down further. Stick close to the 3-hour LOW / 1.5–2 hour HIGH window and check for tenderness rather than cooking on autopilot.
- Balance the sauce. The rice vinegar isn’t just a flourish — it cuts through the soy sauce and brown sugar so the dish reads as savory-sweet instead of just sweet. If you prefer things sweeter, add brown sugar back a tablespoon at a time rather than doubling up on both soy sauce and sugar.
- Save the green onions for the end. Adding them at the very start turns them mushy and dull by the time the dish is done. Stir in half at the finishing stage and save the rest for a fresh garnish.
- Flank steak, sirloin, or strip steak all work well here — use whichever cut is on sale or already in your freezer. For extra insurance on tenderness, a thin-sliced flank-cut chuck roast is a more forgiving substitute for longer cook times, or you can velvet flank steak in a bit of baking soda before coating it in cornstarch.
- If the sauce seems thin after the slurry step, let it cook a few extra minutes on HIGH with the lid off to reduce further.
- Add delicate vegetables like broccoli near the end of cooking, not the beginning, so they stay bright and don’t turn mushy.
Easy Variations
Mongolian Beef and Broccoli
Add 3–4 cups of broccoli florets during the last 20–30 minutes of cooking, or steam them separately and stir in just before serving so they stay crisp-tender.
Ground Beef Mongolian Beef
For a faster weeknight version, brown 1½ lbs ground beef in a skillet, drain the fat, then simmer it in the same sauce mixture on the stovetop for 10–15 minutes until thickened. This skips the slow cooker entirely on nights when you’re short on time and sidesteps the lean-cut tenderness issue.
Healthier, Lighter Version
Use coconut aminos instead of soy sauce and choose a leaner cut like sirloin to cut back on sodium without losing flavor. The sauce is already lighter on sugar than a typical Mongolian beef recipe, so no further adjustment is needed there.
Spicy Mongolian Beef
Increase the red pepper flakes to 1 teaspoon, or stir in a tablespoon of sriracha with the sauce ingredients for more heat throughout.
How to Serve Crockpot Mongolian Beef
- Over steamed white or brown rice
- Tucked into lettuce wraps for a lighter option
- Over noodles in place of rice
- Alongside steamed or roasted broccoli and a side of egg rolls for a full family-style dinner
Storage and Reheating
Refrigerate leftovers in an airtight container for up to 4 days. Reheat gently on the stovetop or in the microwave, adding a small splash of water or broth if the sauce has thickened too much. This recipe also freezes well: cool completely, transfer to a freezer-safe container, and freeze for up to 3 months. Thaw overnight in the fridge before reheating.
Frequently Asked Questions
Is this like P.F. Chang’s Mongolian beef?
This recipe is inspired by the sweet, savory flavor of that popular restaurant-style dish, though it’s a homemade, slow-cooker version and isn’t an official or licensed copycat recipe.
What’s the best cut of beef for Mongolian beef?
Flank steak is a classic choice because it slices thin easily, but because it’s lean, don’t overcook it—this recipe uses a shorter cook time to keep it tender rather than stringy. Sirloin and strip steak both work well too.
Why is the cook time shorter than other slow cooker recipes?
Flank steak and sirloin have very little internal fat or connective tissue. Cooking them low and slow for too long tightens the muscle fibers and pushes out moisture, leaving the beef dry and chewy instead of tender. Three hours on LOW (or 1.5–2 hours on HIGH) is enough to cook the beef through and let the flavors meld without overdoing it.
Can I make this in the Instant Pot instead of a slow cooker?
Yes — see the Instant Pot method above. It comes together in well under an hour total instead of several hours.
Can I use ground beef instead of steak?
Yes, though the texture and cooking method change. See the Ground Beef Mongolian Beef variation above for a quicker stovetop version that also avoids the lean-cut tenderness issue.
Why isn’t my sauce thickening?
Make sure the cornstarch slurry is fully dissolved in cold water before stirring it in, and let the dish cook for the full 15 minutes on HIGH afterward. If it’s still thin, let it cook a few more minutes with the lid off.
Why does this recipe use rice vinegar?
A tablespoon of rice vinegar balances the soy sauce and brown sugar so the sauce doesn’t taste flat or overly sweet. It’s a small addition that makes a noticeable difference in depth of flavor.
Is this a healthy recipe?
It’s a protein-forward dish, though the sauce does contain added sugar. See the lighter variation above for a lower-sodium version using coconut aminos and a leaner cut of beef.
Can I double this recipe for a crowd?
Yes — this recipe doubles well for a holiday meal or family gathering. Use a 7- or 8-quart slow cooker to fit the extra volume, and the cook time stays about the same; check the beef a little early for tenderness.
Conclusion
This crockpot Mongolian beef checks every box for a weeknight dinner that doesn’t feel like a compromise — minimal hands-on time, a genuinely takeout-worthy sauce, and beef that turns out tender every time thanks to a cook time built around the cut of meat, not against it. Whether you’re feeding a busy weeknight table or scaling it up for a family gathering, it’s a reliable dinner to add to the rotation.
Load the slow cooker, let it do the work, and finish with a quick thickening step for that glossy, restaurant-style sauce over rice.
