Slow Cooker Mongolian Beef – Tender, Saucy, and Simple
If you love takeout-style Mongolian beef but want an easier, hands-off version, this slow cooker recipe is your new go-to. It’s rich, savory, slightly sweet, and packs that glossy sauce you can’t stop spooning over rice. The best part: you set it up in the morning and come back to melt-in-your-mouth beef.
No wok flipping, no fuss, just simple prep and big flavor. This is comfort food that fits into busy days and weeknight routines.
Slow Cooker Mongolian Beef - Tender, Saucy, and Simple
Ingredients
Method
- Slice the beef: Cut the flank steak into thin strips against the grain.This keeps the meat tender. Pat dry with paper towels to remove excess moisture.
- Coat with cornstarch: Toss the beef with 1/4 cup cornstarch until evenly coated. Shake off any extra.The coating helps thicken the sauce later and creates a silky texture.
- Optional sear: Heat oil in a skillet over medium-high. Sear the beef in batches for 30–45 seconds per side. You’re not cooking it through—just getting a little color.This step adds flavor, but you can skip it if you’re short on time.
- Make the sauce: In a bowl, whisk soy sauce, brown sugar, beef broth, garlic, ginger, rice vinegar, sesame oil, and red pepper flakes. Taste and adjust. It should be savory-sweet with a gentle tang.
- Load the slow cooker: Add the beef to the slow cooker.Pour the sauce over the top and toss lightly. Cover with the lid.
- Cook low and slow: Cook on LOW for 3.5–4.5 hours or HIGH for 2–2.5 hours. The beef should be tender but not shredded like pot roast.
- Add green onions (and veggies): During the last 20–30 minutes, stir in sliced green onions.If adding veggies like broccoli or snap peas, add them now so they stay crisp-tender.
- Thicken if needed: If the sauce is too thin, stir in a cornstarch slurry (1 tablespoon cornstarch mixed with 1 tablespoon water). Cook 10–15 more minutes until glossy and thick.
- Finish and serve: Taste and adjust seasoning—add a splash more vinegar for brightness or a pinch of sugar if you want sweeter. Serve over rice or noodles.Garnish with extra green onions and sesame seeds.
What Makes This Special
Slow Cooker Mongolian Beef brings together a tender cut of beef, a silky soy-ginger sauce, and the low, steady heat that makes everything fall-apart delicious. You still get the familiar flavors—soy sauce, brown sugar, garlic, and ginger—without standing over a hot pan.
The sauce thickens beautifully in the slow cooker, wrapping every strip of beef in a glossy glaze.
It’s also flexible. You can add veggies near the end, adjust sweetness, or heat it up with red pepper flakes. It’s the kind of recipe that feels like takeout but tastes fresher and cleaner, with ingredients you recognize.
What You’ll Need
- 2 pounds flank steak (or sirloin), thinly sliced against the grain
- 1/4 cup cornstarch (for coating the beef)
- 3/4 cup low-sodium soy sauce
- 1/2 cup brown sugar (light or dark)
- 1/2 cup beef broth (or water)
- 4 cloves garlic, minced
- 1 tablespoon fresh ginger, grated (or 1 teaspoon ground ginger in a pinch)
- 1–2 tablespoons rice vinegar (to balance the sweetness)
- 1–2 teaspoons sesame oil (for aroma)
- 1/2–1 teaspoon red pepper flakes (optional, for heat)
- 2–3 green onions, sliced (plus more for garnish)
- 1 tablespoon cornstarch + 1 tablespoon water (optional slurry to thicken, if needed)
- 2 tablespoons neutral oil (optional, for a quick sear)
- Sesame seeds, for garnish (optional)
- Cooked rice or noodles, for serving
- Optional veggies: broccoli florets, snap peas, or bell peppers
Instructions
- Slice the beef: Cut the flank steak into thin strips against the grain.This keeps the meat tender. Pat dry with paper towels to remove excess moisture.
- Coat with cornstarch: Toss the beef with 1/4 cup cornstarch until evenly coated. Shake off any extra.The coating helps thicken the sauce later and creates a silky texture.
- Optional sear: Heat oil in a skillet over medium-high. Sear the beef in batches for 30–45 seconds per side. You’re not cooking it through—just getting a little color.This step adds flavor, but you can skip it if you’re short on time.
- Make the sauce: In a bowl, whisk soy sauce, brown sugar, beef broth, garlic, ginger, rice vinegar, sesame oil, and red pepper flakes. Taste and adjust. It should be savory-sweet with a gentle tang.
- Load the slow cooker: Add the beef to the slow cooker.Pour the sauce over the top and toss lightly. Cover with the lid.
- Cook low and slow: Cook on LOW for 3.5–4.5 hours or HIGH for 2–2.5 hours. The beef should be tender but not shredded like pot roast.
- Add green onions (and veggies): During the last 20–30 minutes, stir in sliced green onions.If adding veggies like broccoli or snap peas, add them now so they stay crisp-tender.
- Thicken if needed: If the sauce is too thin, stir in a cornstarch slurry (1 tablespoon cornstarch mixed with 1 tablespoon water). Cook 10–15 more minutes until glossy and thick.
- Finish and serve: Taste and adjust seasoning—add a splash more vinegar for brightness or a pinch of sugar if you want sweeter. Serve over rice or noodles.Garnish with extra green onions and sesame seeds.
How to Store
Let leftovers cool, then transfer to an airtight container. Keep in the fridge for up to 4 days. Reheat gently on the stove over low heat or in the microwave, adding a splash of water if the sauce thickens too much.
For freezing, store in a freezer-safe container for up to 2 months.
Thaw in the fridge overnight, then reheat as above. Veggies like broccoli may soften after freezing, so consider adding them fresh when reheating.
Benefits of This Recipe
- Set it and forget it: Minimal active time, perfect for busy days.
- Restaurant-style flavor: You get a glossy, rich sauce with pantry staples.
- Customizable: Adjust sweetness, spice, and veggies to suit your taste.
- Budget-friendly: Flank or sirloin stretches well, especially when served with rice.
- Great for meal prep: Holds up well in the fridge and reheats nicely.
Pitfalls to Watch Out For
- Overcooking: Mongolian beef should be tender but sliceable. Cooking too long can make it stringy.Check at the low end of the time range.
- Sauce too sweet: Brown sugar balances the soy, but you don’t need a dessert-level sweetness. Start with the listed amount and adjust with rice vinegar for balance.
- Skipping the cornstarch: Without it, the sauce won’t cling well. Coat the beef evenly and use a slurry if needed at the end.
- Salty sauce: Use low-sodium soy sauce and avoid extra salt.If it tastes too salty, add water or broth and a pinch more sugar to balance.
- Adding veggies too early: They’ll turn mushy. Add them in the last 20–30 minutes.
Alternatives
- Different cuts: Try sirloin, flat iron, or thin-cut chuck. If using chuck, cook closer to the longer end for tenderness.
- Swap the sweetener: Use honey or coconut sugar instead of brown sugar.Honey will yield a slightly lighter, glossy finish.
- Gluten-free: Use tamari or a certified gluten-free soy sauce. Check your broth and cornstarch too.
- Low-sugar: Reduce sugar to 1/3 cup and add more ginger and vinegar for flavor balance. You can also use a sugar alternative you like for cooking.
- Extra heat: Add fresh sliced chili, more red pepper flakes, or a spoonful of chili crisp at the end.
- Stovetop pressure cooker: Cook on high pressure for 10 minutes with quick release, then thicken with slurry and add green onions.
FAQ
Can I make this without searing the beef first?
Yes.
Searing adds depth, but it’s optional. The slow cooker still develops plenty of flavor, especially with garlic, ginger, and the sauce.
What if I can’t find flank steak?
Sirloin works well and stays tender. Flat iron and thinly sliced chuck can also work; just monitor cook time so it doesn’t over-shred.
How do I keep the sauce from getting too thick when reheating?
Add a splash of water or beef broth and warm gently.
Stir as it heats so the cornstarch loosens and the sauce turns glossy again.
Can I add vegetables from the start?
It’s better not to. Add broccoli, snap peas, or bell peppers in the last 20–30 minutes so they stay bright and crisp-tender.
Is this very sweet?
It’s mildly sweet with a savory backbone. If you prefer less sweetness, reduce the sugar to 1/3 cup and use the full 2 tablespoons of rice vinegar for balance.
What can I serve this with besides rice?
Try steamed cauliflower rice, garlic noodles, or sautéed greens.
It also makes great lettuce wraps with a sprinkle of sesame seeds.
Can I prep this the night before?
Yes. Slice and cornstarch the beef, mix the sauce, and store separately in the fridge. In the morning, combine in the slow cooker and start cooking.
Why is my beef tough?
It may be sliced with the grain or cooked too long.
Make sure to cut against the grain into thin strips and check for doneness a bit earlier next time.
Final Thoughts
Slow Cooker Mongolian Beef brings that takeout-style flavor to your table with very little effort. The beef turns tender, the sauce turns glossy, and the whole thing feels special without being fussy. Keep the basics in mind—thin slices, balanced sauce, and a quick thicken at the end—and you’ll have a reliable, crowd-pleasing dinner any night of the week.
Serve it hot over rice, sprinkle with green onions, and enjoy the kind of meal that makes seconds almost guaranteed.
