Tender Slow Cooker Mongolian Beef Recipe
Skip the takeout menu and make this sweet-savory favorite at home with almost no effort. This Slow Cooker Mongolian Beef has tender slices of beef in a rich, glossy sauce that clings to every bite. It’s the kind of meal that tastes restaurant-worthy but comes together with pantry staples and a few minutes of prep.
Toss everything in the slow cooker, set it, and come back to a cozy dinner that fills the kitchen with amazing aroma.
What Makes This Special
This version keeps the flavors you love—ginger, garlic, and a slightly sweet soy glaze—without standing at the stove. The slow cooker does the heavy lifting, turning budget-friendly beef into fork-tender strips. A touch of brown sugar caramelizes into a silky sauce, and a cornstarch slurry makes it just the right thickness.
It’s family-friendly, reheats well, and pairs beautifully with rice, noodles, or steamed veggies.
What You’ll Need
- 2 pounds flank steak, thinly sliced against the grain (skirt steak or sirloin also work)
- 1/2 cup low-sodium soy sauce
- 1/2 cup beef broth (or water)
- 3/4 cup brown sugar (light or dark)
- 4 cloves garlic, minced
- 1 tablespoon fresh ginger, grated (or 1 teaspoon ground ginger)
- 2 tablespoons cornstarch (for the beef)
- 2 tablespoons cornstarch + 2 tablespoons water (for slurry)
- 2 tablespoons sesame oil (to add richness)
- 1/4 teaspoon red pepper flakes (optional, for heat)
- 2–3 green onions, sliced (for garnish)
- 1–2 teaspoons toasted sesame seeds (optional garnish)
- Cooked rice or noodles, for serving
How to Make This Slow Cooker Mongolian Beef Recipe
- Slice the beef thin. Cut the flank steak into thin strips against the grain. This keeps it tender after slow cooking.
- Toss with cornstarch. Add 2 tablespoons cornstarch to the sliced beef and coat evenly. This step helps the sauce cling and thicken later.
- Mix the sauce. In a bowl, whisk together soy sauce, beef broth, brown sugar, garlic, ginger, sesame oil, and red pepper flakes if using.
- Load the slow cooker. Place the coated beef in the slow cooker.
Pour the sauce over and stir to distribute.
- Cook low and slow. Cover and cook on Low for 3–4 hours or on High for 1.5–2 hours, until the beef is tender but not falling apart.
- Thicken the sauce. Stir together 2 tablespoons cornstarch and 2 tablespoons water. Pour into the slow cooker, stir, and cook for 15–20 minutes more on High until the sauce is glossy and coats the beef.
- Finish and serve. Taste and adjust with a splash of soy for salt or a pinch of sugar for sweetness. Garnish with green onions and sesame seeds.
Serve over steamed rice or noodles.
Storage Instructions
- Refrigerate: Cool completely, then store in an airtight container for up to 4 days.
- Freeze: Freeze in portions for up to 3 months. Thaw overnight in the fridge.
- Reheat: Warm gently on the stovetop over low heat, adding a splash of water or broth to loosen the sauce. Microwave in 30-second bursts, stirring between.
- Make-ahead tip: Slice and cornstarch the beef, mix the sauce, and refrigerate separately up to 24 hours.
In the morning, combine in the slow cooker.
Benefits of This Recipe
- Hands-off cooking: Minimal prep and no searing required. Great for busy weekdays.
- Budget-friendly: Flank or sirloin becomes tender without expensive cuts.
- Consistent results: The slow cooker keeps the sauce balanced and the beef juicy.
- Customizable: Adjust sweetness, heat, and thickness to your taste.
- Meal prep friendly: Stores and reheats well for leftovers or lunches.
Common Mistakes to Avoid
- Slicing with the grain: This makes the beef chewy. Always slice against the grain, as thin as you can.
- Skipping cornstarch on the beef: It helps the sauce cling and improves texture.
Don’t skip it.
- Overcooking: Beef can dry out if left too long. Check for tenderness at the lower end of the time range.
- Too sweet or too salty: Use low-sodium soy sauce and adjust sugar to taste. You can always add more later.
- Not thickening properly: Add the cornstarch slurry at the end and give it time to simmer so it activates.
Variations You Can Try
- Veggie boost: Add sliced bell peppers, broccoli florets, or snap peas in the last 30–45 minutes so they stay crisp-tender.
- Spicy Mongolian beef: Increase red pepper flakes or stir in chili-garlic sauce or gochujang for a kick.
- Orange twist: Add 1–2 teaspoons orange zest and 2 tablespoons orange juice for a bright citrus note.
- Honey swap: Replace part of the brown sugar with honey for a lighter sweetness and floral flavor.
- Gluten-free: Use tamari or coconut aminos instead of soy sauce and confirm your cornstarch is gluten-free.
- Lean cut: Try sirloin tip or eye of round, sliced thin.
It won’t be as rich as flank but still tasty when not overcooked.
FAQ’s For Slow Cooker Mongolian Beef Recipe
Can I make this without a slow cooker?
Yes. Sauté the cornstarch-coated beef in a large skillet with a bit of oil until browned. Whisk the sauce, pour it in, and simmer for 5–8 minutes.
Add the slurry and cook until thickened and the beef is cooked through. Keep the heat medium to prevent burning.
Do I need to sear the beef first?
No. Searing adds depth, but it’s optional here.
The sauce is flavorful enough, and skipping searing keeps this recipe simple and weeknight-friendly.
How do I keep the sauce from getting too sweet?
Use low-sodium soy sauce and start with 1/2 cup brown sugar. Taste at the end and add more only if needed. A splash of rice vinegar or a squeeze of lime can balance sweetness.
What side dishes work best?
Steamed jasmine rice, brown rice, or rice noodles are classic.
For veggies, try roasted broccoli, bok choy, or a simple cucumber salad to cut through the richness.
Can I add vegetables directly to the slow cooker?
Yes, but add them later. Broccoli, peppers, or snap peas go in during the last 30–45 minutes to avoid turning mushy. Carrots can handle a bit longer.
What if my sauce is still thin after adding the slurry?
Let it cook uncovered on High for another 10–15 minutes.
If needed, add a second small slurry (1 teaspoon cornstarch mixed with 1 teaspoon water) and simmer again.
Which cut of beef is best?
Flank steak is classic for Mongolian beef. Skirt steak and sirloin also work well. The key is slicing thin against the grain for tenderness.
Can I reduce the sugar for a lighter version?
Yes.
Cut the brown sugar to 1/2 cup or even 1/3 cup, then taste and adjust at the end. You can also add extra ginger and a splash of vinegar for balance.
Is this recipe freezer-friendly?
Very. Freeze cooked and cooled beef with sauce in airtight containers.
Thaw overnight and reheat gently, adding a splash of water if the sauce is too thick.
In Conclusion
This Slow Cooker Mongolian Beef is simple, reliable, and packed with flavor. It turns a handful of ingredients into a comforting, glossy-sauced dinner that feels special without much effort. Keep it classic with rice and green onions, or make it your own with spice, citrus, or veggies.
Either way, it’s a weeknight win you’ll want on repeat.
Slow Cooker Mongolian Beef Recipe
Ingredients
- 2 pounds flank steak, thinly sliced against the grain (skirt steak or sirloin also work)
- ½ cup low-sodium soy sauce
- ½ cup beef broth (or water)
- ¾ cup brown sugar (light or dark)
- 4 cloves garlic, minced
- 1 tablespoon fresh ginger, grated (or 1 teaspoon ground ginger)
- 2 tablespoons cornstarch (for the beef)
- 2 tablespoons cornstarch + 2 tablespoons water (for slurry)
- 2 tablespoons sesame oil (to add richness)
- ¼ teaspoon red pepper flakes (optional, for heat)
- 2–3 green onions, sliced (for garnish)
- 1–2 teaspoons toasted sesame seeds (optional garnish)
- Cooked rice or noodles, for serving
Instructions
- Slice the beef thin. Cut the flank steak into thin strips against the grain. This keeps it tender after slow cooking.
- Toss with cornstarch. Add 2 tablespoons cornstarch to the sliced beef and coat evenly. This step helps the sauce cling and thicken later.
- Mix the sauce. In a bowl, whisk together soy sauce, beef broth, brown sugar, garlic, ginger, sesame oil, and red pepper flakes if using.
- Load the slow cooker. Place the coated beef in the slow cooker. Pour the sauce over and stir to distribute.
- Cook low and slow. Cover and cook on Low for 3–4 hours or on High for 1.5–2 hours, until the beef is tender but not falling apart.
- Thicken the sauce. Stir together 2 tablespoons cornstarch and 2 tablespoons water. Pour into the slow cooker, stir, and cook for 15–20 minutes more on High until the sauce is glossy and coats the beef.
- Finish and serve. Taste and adjust with a splash of soy for salt or a pinch of sugar for sweetness. Garnish with green onions and sesame seeds. Serve over steamed rice or noodles.
