Easy Mongolian Beef Slow Cooker Recipe

This Mongolian Beef Slow Cooker Recipe is a Chinese-American dish that is super easy and tastes amazing with bold flavors, and is easy to make. Just toss everything in the slow cooker, and your kitchen will smell incredible. This easy recipe is for the entire family as it has a sweet-savory sauce with soy sauce and green onions. Your crockpot makes it easy and even more delicious!

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The recipe has tender beef with a sweet, delicious, savory sauce. Serve it over white or brown rice, and even your picky eaters will be excited for dinner time. The best part is that there is minimal work, with maximum delicious flavors. Try it any night!

On a lazy weeknight, you can enjoy an Asian-inspired dish in the comfort of your own home. This Easy crockpot Mongolian beef brings the savory-sweet vibes of your favorite Chinese restaurant to your kitchen with minimal effort.

This great recipe has tender pieces of flank steak thinly sliced, lightly coated in cornstarch, simmering in a sauce packed with fresh ginger, garlic, and a kick of red chili peppers. The tender beef cooks slowly to perfection, bursting with flavor. It’s a family-friendly meal that pairs perfectly with hot cooked rice for a cozy, fuss-free dinner.

Why You Will Love This Recipe: 

• Effortless slow cooker magic. By simply adding the ingredients to your crockpot, you allow the flavors to meld slowly, creating a tender, melt-in-your-mouth texture without the need for constant attention—ideal for busy days or freezer meal prep.
• Balanced savory and sweet flavors. The combination of soy sauce and brown sugar produces a rich, delicious sauce that strikes a perfect balance between salty depth and a subtle sweet finish, enhanced by the zing of fresh ginger and garlic.
• Simple ingredients, tons of flavor. With straightforward pantry staples like cornstarch, soy sauce, and spices, this recipe transforms simple ingredients into a fabulous main course with authentic Asian food taste.

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Equipment Needed

• Crockpot/Slow Cooker
• Sharp Knife for slicing
• Garlic Peeler Skin Remover takes the frustration out of fresh garlic.
• Hand Pull String Garlic Mincer Onion Cutter, my new favorite, saves so much time.

Ingredients for Crockpot Mongolian Beef

• 1.5 pounds of Flank Steak
• 1 medium Onion, sliced thin
• 1/4 cup of Corn Starch
• 3/4 cup of Soy Sauce
• 2 tablespoons of Sesame Oil
• 1/2 cup of Sugar or Monk Fruit sweetener
• 3/4 cup of Water
• 3 cloves of minced Garlic
• 1 tablespoon of Minced Fresh Ginger
• 1/4 teaspoon Red Pepper Flakes or 1 teaspoon of Sriracha
• Garnish with sliced Green Onions and Sesame Seeds
• Low for 4 hours (or high for 1.5 to 2 hours, but not recommended)

How to Make Easy Slow Cooker Mongolian Beef

1. Slice the Beef: Cut the flank steak into thin slices, about 1/4 inch thick. Pro tip: If the beef is slightly frozen, it’s way easier to slice!
2. Coat the Beef: Put the sliced beef and cornstarch in a large ziplock bag. Seal it tight, then shake and mix until all the beef is coated.
3. Add Onions: Place onion slices at the bottom of your slow cooker.
4. Layer the Beef: Spread the coated beef slices on top of the onions.
5. Make the Sauce: In a medium bowl, mix soy sauce, sesame oil, sugar (or Monk fruit sweetener), and water. Whisk until it’s smooth. Add minced garlic, minced ginger, and a pinch of red pepper flakes or a dash of sriracha for a little kick (skip if you want it mild).
6. Pour and Cook: Pour the sauce over the beef in the slow cooker. Cover and cook on low for 4 hours.
7. Check Halfway: After 2 hours, quickly lift the lid (don’t keep it off for more than a minute—it takes 30 minutes to heat back up!) and make sure the beef is covered in sauce. Stir gently if needed.
8. Add Veggies (Optional): If you want to add bell peppers or broccoli, toss them in 1 hour before the cooking time is up.
9. Serve and Enjoy: When the beef is done, it’ll be tender and full of flavor. Garnish with sliced Green Onions and Sesame Seeds. Serve it with rice or your favorite side!

Must-Have Ingredients and Backups

• Flank Steak is a favorite cut of meat for Mongolian beef because it is lean, soaks up flavors, and gets super tasty when thinly sliced and the the slow cooker. If you prefer, sirloin steak can be used as an alternative.
• Soy sauce gives Mongolian beef its classic umami kick, making every bite super flavorful. For gluten-free or soy-free options, try tamari or coconut aminos as great substitutes.
• Fresh ginger and fresh garlic add a zesty, bold kick that makes the whole dish pop with flavor. Ground ginger or garlic powder can be used in a pinch, but freshly minced versions will give you the most vibrant results.
• Cornstarch is the secret to that silky sauce that clings beautifully to the beef. Arrowroot powder or potato starch is a perfect gluten-free alternative.
• A little sriracha or red pepper flakes brings a nice, warm kick to balance the flavors. You can tweak the amount to match your family’s spice level or skip it for a milder taste.
• Toasted Sesame Oil: sesame oil amplifies the nutty fragrance and richness of the dish.

First Time Tips for Your Crockpot Beef

1. Slice the flank steak into thin strips against the grain. This helps ensure a tender bite and prevents the meat from becoming tough in the slow cooker. Aim for slices about ¼ inch thick to allow the cornstarch to coat the beef properly.
2. Use fresh ginger and garlic for the best flavor; Freshly minced ginger and garlic release essential oils that create an aromatic base for the sauce. Avoid pre-minced or powdered alternatives if possible.
3. Cook low and slow for tenderness; Set your crockpot to low for about four hours rather than high for two. Slow cooking breaks down the beef fibers gently, encouraging melt-in-your-mouth tenderness and deeper flavor.
4. Garnish with fresh green onions and sesame seeds. Just before serving, sprinkle sliced green onions and toasted sesame seeds over the dish. These add freshness, texture, and an inviting visual appeal.

Recipe Variations

• Add More Vegetables: Include sliced bell peppers, snap peas, or broccoli florets for extra color, nutrition, and delicious texture contrast in your slow cooker meal.
• Make It Spicy: Increase the sriracha or red pepper flakes to your like a hotter version of this classic dish, perfect for those who enjoy a bit of heat with their Asian comfort food.
• Double the Sauce: If you prefer more sauce for dipping or drizzling over rice, simply double the soy sauce and brown sugar proportions in the recipe.
• Serve as a Stir Fry: For a quicker variant, skip the slow cooker and use a large skillet
   to stir fry the beef and sauce ingredients in a hot skillet for a fast, weeknight-friendly meal.

Solutions for Common Problems with Crockpot Mongolian Beef

1. Beef is Tough or Chewy. Ensure that the flank steak is sliced thinly and against the grain to promote tenderness. Slow cook on low rather than high for a more gentle cooking process that breaks down fibers effectively.
2. The sauce is Too Thin. If the sauce isn’t thickening, add a slurry of cornstarch mixed with water during the last 30 minutes of cooking and switch to high heat to start the sauce be more thick.
3. Meat Sticks Together. Make sure to coat the beef slices evenly in cornstarch before cooking to prevent clumping.

Frequently Asked Questions:

Can I use other types of beef for this recipe?

Yes, skirt steak, sirloin steak, or even well-trimmed ribeye can substitute for flank steak. 

Is it possible to make this recipe without a slow cooker?

Absolutely. You can stir-fry the beef and then simmer the sauce on the stove for a faster version, adjusting cooking times accordingly.

How can I make this dish less sweet?

Reduce the brown sugar amount by half and adjust according to your taste.

Can I add more vegetables directly to the slow cooker?

Yes, add vegetables like bell peppers or broccoli during the last hour of cooking to keep them from over-softening.

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