This Slow Cooker Mongolian Beef recipe is an easy, no-stress crockpot recipe that is packed with delicious flavor and tender Mongolian beef!

This recipe is best served with a bed of hot sticky rice, a side of oven roasted broccoli and crunchy cabbage salad.

A white plate full of Slow Cooker Mongolian Beef on  bed of brown rice.

Why This Recipe Works

  • Tender and flavorful flank steak. One of the best parts about this recipe is that the steak gets so flavorful and tender because it is slowly cooked in the crockpot in all the juices from the meat and the sauce. The meat absorb that flavor and remains tender since it isn’t brought to a high heat and cooked in just a few minutes. 
  • Plenty of sauce to go around. I’ve created this recipe so there is plenty of sauce for the meat and extra sauce to spoon over the rice. It’s never fun when you make a meal and you wish it was more saucy! Not the case here! 
  • One pot Mongolian beef. This recipe is amazing because you only use one pot! No need to pre-cook or sear the meat, no need to mix the sauce in a different bowl. It makes meal prep and clean up a breeze! 

Ingredient Notes

Slow Cooker Mongolian Beef ingredients on a white background.
  • Cornstarch: Coating the meat in cornstarch helps the meat cook more evenly because the cornstarch acts as a protector from meat at the bottom cooking faster than meat at the top. It also helps seal in some of the juices, making the meat more tender.
  • Flank Steak: Cut the flank steak in strips. You can use skirt steak as a substitute.
  • Brown Sugar: I wanted to get the ratio of brown sugar just right! This is enough brown sugar to make a sweet, glaze-like sauce, but not too much that it is overly sweet.
  • Sesame Oil: I don’t have a good substitution recommendation for this because the sesame oil really helps give that nice Asian flavor to the sauce. It also balances out the flavor and saltiness of the soy sauce. 

Step-by-Step Instructions

  1. Slice the flank steaks. Cut them perpendicular to the grains for the best cut.  
Flank steaks cut into thin strips on a white cutting board.
  1. Coat in cornstarch. Place the cornstarch and steak slices in a large Ziplock bag. Seal and toss to coat. 
  2. Place the coated flank steak in the slow cooker. 
  1. Add the remaining ingredients except for the green onions. Stir everything together. Cover and cook on LOW for 4-5 hours. 
  1. Right before serving, stir in the green onions. Serve over a bed of rice.
Slow Cooker Mongolian Beef in a black slow cooker.

Recipe Tips

When cutting flank steak, it’s recommended to cut against the grain (perpendicular to it) which helps make the meat more tender when cooked and easier to chew. Putting the steaks in the freezer for 15-20 minutes before cutting can make it easier to cut.

If you are looking for an alternative to flank steak, the best would probably be skirt steak. Typically flank steak is more expensive, but skirt steak is very similar in texture and flavor.

Feel free to add some broccoli to the slow cooker for a dish that tastes like P.F. Changs’ Mongolian beef and broccoli!

You can use the ginger in the ginger squeeze tubes if you are looking to cut time so you don’t have to grate fresh ginger but still want the flavor of the fresh ginger. If using dried ginger, 1/2 teaspoon = 2 teaspoons freshly grated ginger.

Make Ahead, Storing, and Freezing

If making ahead of time, or if you have leftovers, store the Mongolian beef in an airtight container in the fridge for 3-4 days. Note: the beef will be the most tender the day of since reheating the beef after being cooled can make the meat get dry or tough. 

To freeze, I would recommend freezing it with the meat raw. Prepare the meat and the sauce and store it together in an airtight container or Ziplock bag in the freezer for up to 3 months. Remove from the fridge and thaw, then transfer to the slow cooker. Skip the cornstarch. When the meal is starting to boil in the slow cooker, take some of the sauce and put it in a bowl and add the cornstarch to make a cornstarch slurry. Then add that to the slow cooker and mix. 

You won’t get the same results with the meat as you would coating it in the cornstarch, but cornstarch loses its purpose when frozen. 

Slow Cooker Mongolian Beef on a bed of brown rice.

FAQs

Why is Mongolian beef so tender?

One of the biggest reasons is that the meat is slowly cooked in the crockpot in the Mongolian beef sauce. The meat absorbs that flavor and liquid and it makes it taste amazing and so tender at the same time!   

Where does Mongolian beef come from?

Mongolian beef is a dish that originates from Taiwan. 

What can I substitute for flank steak?

A good substitute for flank steak is skirt steak. It is pretty similar in flavor and texture and will give you a similar result for the Mongolian beef dish.

Slow Cooker Mongolian Beef on a plate topped with green onions.

More Slow Cooker Recipes

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A white plate with Slow Cooker Mongolian Beef topped with sliced green onions on brown rice.
Print Review
5 from 2 votes

Slow Cooker Mongolian Beef

Tender flank steak is cooked in the slow cooker amongst a delicious soy sauce based sauce. Serve this amazing meat over a bed of rice and garnish with green onions for a decadent and delicious meal.
Prep Time: 10 mins
Cook Time: 4 hrs
Total Time: 4 hrs 10 mins
Servings: 8 servings

Ingredients
 

  • 2 lbs flank steak - thinly sliced (about 1/4") against the grain
  • 1/3 cup cornstarch
  • 1 1/2 tablespoons toasted sesame oil
  • 1 1/2 teaspoons garlic - minced
  • 2 teaspoons fresh ginger - grated
  • 1 cup low sodium soy sauce
  • 2/3 cup light brown sugar - packed
  • 1 1/4 cups water
  • 4 green onions - sliced

Equipment

Instructions
 

  • Place the cornstarch in a large ziplock bag. Add the flank steak slices, seal the bag, and toss to coat. 
  • Place the coated flank steak in the slow cooker. 
  • Add the sesame oil, garlic, ginger, soy sauce, brown sugar, and water the slow cooker. Stir everything together. Cover and cook on LOW for 4-5 hours. 
  • Right before serving stir in the green onions. Serve over a bed of rice. 

Notes

When cutting flank steak, cut against the grain (perpendicular to it). It helps make the meat more tender when cooked and easier to chew. Putting the steaks in the freezer for 15-20 minutes before cutting can make it easier to cut.
Skirt steak is the best substitution for flank steak.
You can use the ginger in the ginger squeeze tubes if you are looking to cut time so you don’t have to grate fresh ginger but still want the flavor of the fresh ginger. If using dried ginger, 1/2 teaspoon = 2 teaspoons freshly grated ginger.
Make Ahead, Storing, and Freezing
Store the Mongolian beef in an airtight container in the fridge for 3-4 days. Note: the beef will be the most tender the day of since reheating the beef after being cooled can make the meat get dry or tough. 
To freeze, prepare the meat (raw) and the sauce and store it together in an airtight container or Ziplock bag in the freezer for up to 3 months. Remove from the fridge and thaw, then transfer to the slow cooker. Skip the cornstarch. When the meal is starting to boil in the slow cooker, take some of the sauce and put it in a bowl and add the cornstarch to make a cornstarch slurry. Then add that to the slow cooker and mix. 

Nutrition

Calories: 289kcal (14%)Carbohydrates: 26g (9%)Protein: 26g (52%)Fat: 8g (12%)Saturated Fat: 3g (15%)Polyunsaturated Fat: 1gMonounsaturated Fat: 3gCholesterol: 68mg (23%)Sodium: 1131mg (47%)Potassium: 489mg (14%)Fiber: 1g (4%)Sugar: 18g (20%)Vitamin A: 60IU (1%)Vitamin C: 1mg (1%)Calcium: 51mg (5%)Iron: 3mg (17%)
Course: Main Course
Cuisine: Asian
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