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This Slow Cooker Mongolian Beef is tender, flavorful, and ridiculously easy to make. Thinly sliced flank steak cooks low and slow in a sweet and savory sauce with brown sugar, soy sauce, garlic, and ginger until it practically melts in your mouth. Serve it over rice for an easy family dinner that’s way better than takeout.
If you love easy Asian-inspired dinners, try this Beef and Broccoli for a quick stir fry version, or this Szechuan Chicken Stir Fry for something with a little more heat. Crockpot Orange Chicken is another slow cooker favorite.
3 Tips That Make or Break This Recipe
A few things to know before you start that will help you get the best results with this recipe.
- Slice the flank steak thin, against the grain. This is the biggest factor in tender Mongolian beef. Aim for strips about ¼-inch thick. Pop the steak in the freezer for 15 to 20 minutes first to make slicing easier.
- Coat every piece of beef in cornstarch. It tenderizes the surface and thickens the sauce as it cooks, giving you that glossy, sticky coating. Shake well in the bag so every piece is evenly coated.
- Use low-sodium soy sauce. The sauce concentrates as it cooks in the slow cooker, so regular soy sauce can make the dish overly salty. You can always add more at the table.
RECIPE WALK-THROUGH
How To Make Slow Cooker Mongolian Beef
See the recipe card below for full, detailed instructions
This recipe comes together with about 10 minutes of hands-on prep, then the slow cooker does the rest. Here’s how to get the best results.
Step 1: Coat the Beef
Add the sliced flank steak and cornstarch to a large resealable plastic bag. Seal it and shake well until every piece is evenly coated.
This step is quick but important. The cornstarch creates a light coating that helps thicken the sauce into that sticky, glossy finish as it cooks.
Step 2: Build the Sauce
Add the sesame oil, minced garlic, ground ginger, beef broth, soy sauce, brown sugar, garlic chili paste, and rice vinegar to the bottom of your slow cooker. Whisk everything together until the brown sugar is mostly dissolved.
The sauce should smell amazing at this point, with that sweet and savory balance that makes Mongolian beef so good.
Start with less chili paste if you’re cooking for kids. A full teaspoon gives a mild, background warmth. You can skip it entirely for sensitive palates, or add more if you like heat.
Step 3: Add the Beef and Carrots
Add the cornstarch-coated flank steak and shredded carrots to the slow cooker. Stir everything together so the beef is fully coated in the sauce.
Don’t stack the beef too thick. Try to spread the pieces out as much as possible so they cook evenly and the sauce can reach all of them.
Step 4: Cook Low and Slow
Cover and cook on HIGH for 2 to 3 hours or LOW for 4 to 5 hours, until the steak is tender and the sauce has thickened. You’ll know it’s done when the beef is fork-tender and the sauce coats the back of a spoon.
If the sauce seems thin at the end, mix 1 tablespoon of cornstarch with 2 tablespoons of cold water and stir it into the slow cooker. Let it cook for another 10 to 15 minutes with the lid off until the sauce thickens up.
Step 5: Finish and Serve
Stir in the green onions right at the end so they stay bright and slightly crisp. Serve the Mongolian beef over white rice, and garnish with sesame seeds.
Add the green onions last. If they cook too long, they’ll turn mushy and lose their color. Stirring them in off the heat or in the last few minutes is all they need.
What to Serve with Mongolian Beef
This Mongolian beef is a full-flavored main dish, so it pairs best with simple sides that let the sauce shine. Serve it over Egg Fried Rice, steamed jasmine rice, Pan Fried Noodles, or Chicken Lo Mein noodles. For a lower-carb option, try it over steamed broccoli or cauliflower rice.
For sides, any of these would be a great match:
- Sauteed Broccoli
- Air Fryer Broccoli
- Vegetable Stir Fry
- Asian Cucumber Salad
- Cabbage Salad
- Ramen Chinese Chicken Salad
Storage Tips
Storage and Reheating
Leftovers: Store in an airtight container in the refrigerator for up to 3 to 4 days. The sauce thickens as it cools, which is totally normal.
Reheating: Warm leftovers in a skillet over medium heat with a splash of water or broth to loosen the sauce back up. The microwave works too, but the stovetop gives you better texture. Heat at 50% power if using the microwave to prevent the beef from getting tough.
Freezing: Let the Mongolian beef cool completely, then transfer to a freezer-safe container or bag. It freezes well for up to 2 to 3 months. Thaw in the refrigerator overnight before reheating.
Frequently Asked Questions
What is the best cut of beef for slow cooker Mongolian beef?
Flank steak is the best choice. It’s lean, flavorful, and becomes incredibly tender when slow cooked. Skirt steak also works well as a substitute. Avoid pre-cut stew meat, which can have inconsistent texture and doesn’t slice thin enough for this recipe. The key is cutting whatever beef you use into thin strips against the grain.
Can I cook this on high vs. low in the slow cooker?
Yes, both work. On HIGH, plan for 2 to 3 hours. On LOW, plan for 4 to 5 hours. The low setting gives you a bit more flexibility with timing if you’re not sure exactly when dinner will be, and the beef will be equally tender either way.
How do I thicken the sauce if it’s too thin?
Mix 1 tablespoon of cornstarch with 2 tablespoons of cold water until smooth, then stir it into the slow cooker. Cook with the lid off for 10 to 15 minutes until the sauce reaches the consistency you want. Always mix the cornstarch with cold water first to avoid lumps.
Can I use a different meat instead of flank steak?
Skirt steak is the closest substitute and works the same way. You can also use thinly sliced sirloin or flat iron steak. For a budget-friendly option, chuck roast cut into thin strips will get very tender in the slow cooker, though it may need a slightly longer cook time. Chicken thighs also work if you want a lighter version, just reduce the cook time to 2 to 3 hours on LOW.
More Easy Asian-Inspired Dinners
- Beef and Broccoli
- Crockpot Orange Chicken
- Kung Pao Chicken
- Ground Beef & Noodle Stir Fry
- Chicken Yakisoba
Slow Cooker Mongolian Beef
Ingredients
- 1 1/2 pounds flank steak thinly sliced against the grain
- 1/4 cup cornstarch
- 1 tablespoon toasted sesame oil
- 4 cloves garlic minced
- 1 teaspoon ground ginger
- 1/2 cup low-sodium beef broth (or water)
- 3/4 cup low-sodium soy sauce
- 1/2 cup brown sugar packed
- 1 teaspoon garlic chili paste
- 1 teaspoon rice vinegar
- 1 cup shredded carrots
- ½ cup green onions cut into 1-inch pieces
- Sesame seeds for garnish
Instructions
- Add the sliced flank steak and cornstarch to a large resealable plastic bag. Seal and shake to coat evenly.
- To the bottom of the slow cooker, add the sesame oil, garlic, ginger, broth, soy sauce, brown sugar, garlic chili paste, and rice vinegar. Whisk to combine.
- Add the coated flank steak and shredded carrots to the slow cooker. Stir to coat the beef in the sauce.
- Cover and cook on HIGH for 2 to 3 hours or on LOW for 4 to 5 hours, until the steak is tender and the sauce has thickened.
- Stir in the green onions. Serve over white rice and garnish with sesame seeds.
Notes
- Slice against the grain. This is the most important step for tender beef. Look for the lines running through the steak and cut across them, not with them. Aim for ¼-inch thick strips.
- Freezer trick for easier slicing. Place the flank steak in the freezer for 15 to 20 minutes before slicing. It firms up just enough for thin, even cuts.
- Use low-sodium soy sauce. The sauce concentrates during cooking, so regular soy sauce can make the dish too salty.
- Cornstarch coating is key. It tenderizes the beef surface and thickens the sauce for that sticky, restaurant-style glaze.
- Make it mild. Reduce or skip the garlic chili paste for less heat. The dish is still packed with flavor from the brown sugar, soy sauce, and ginger.
- Sauce too thin? Mix 1 tablespoon cornstarch with 2 tablespoons cold water. Stir into the slow cooker and cook uncovered for 10 to 15 minutes.
- Add green onions last. Stir them in at the very end so they keep their color and a slight crunch.
- Best rice pairing: Steamed jasmine or long-grain white rice works best. The slightly sticky texture of jasmine rice holds the sauce well.
- Storage: Refrigerate leftovers in an airtight container for 3 to 4 days. Reheat in a skillet with a splash of water or broth.
- Freezing: Cool completely and freeze in an airtight container for up to 2 to 3 months. Thaw overnight in the fridge before reheating.
Nutrition
Nutritional Disclaimer Kristin Maxwell of “Yellow Bliss Road” is not a dietician or nutritionist, and any nutritional information shared is an estimate. For accurate calorie counts and other nutritional values, we recommend running the ingredients through your preferred online nutritional calculator. Calories and other nutritional values can vary depending on which brands were used.
I have tried several of your recipes recently and like them all. Thank you!
For this one, the ingredient list and the instructions (specifically item 2.) don’t match. Would you please double check it and update it? Thank you!
Hi Julie, thanks for the heads up and for your kind feedback. I’ve updated the recipe.