Slow Cooker Mongolian Beef (Better Than Takeout)

Imagine walking through your front door after a chaotic school run or a long shift and being greeted by the sweet, savory, and unmistakably aromatic scent of ginger and garlic. Your kitchen smells like the best neighborhood bistro, but you haven’t touched a pan in hours. This Easy Slow Cooker Mongolian Beef is my secret weapon for those nights when the calendar is full but the family is hungry.

We are skipping the greasy delivery and the high price tag for a dish that delivers tender, velvety ribbons of beef coated in a glossy, dark sauce that clings to every bite. If you can slice a steak and whisk a sauce, you have already mastered this recipe.

Why This Recipe Works

Traditional Mongolian beef relies on a technique called ‘velveting,’ where meat is quickly passed through hot oil to seal in moisture. In this slow cooker version, the cornstarch coating performs a double duty.

It creates a protective barrier around the flank steak, ensuring the fibers remain succulent during the long simmer rather than turning stringy. Using reduced-salt soy sauce allows us to control the seasoning perfectly, preventing the sauce from becoming an salt-bomb as it reduces. The brown sugar doesn’t just add sweetness; it creates the base for that iconic sticky glaze that defines the dish.

Key Ingredients & Notes

• 1 pound flank steak: Always slice against the grain to ensure the beef melts in your mouth rather than feeling chewy.
• 2-3 stalks green onion (or scallion): These provide a fresh, sharp bite that cuts through the richness of the beef.
• 1/4 cup cornstarch: This is the secret to the ‘velvety’ texture and a thick, luscious sauce.
• 1 tsp salt (to taste): Use kosher salt for a more controlled seasoning.
• 1 tsp black pepper (to taste): Freshly cracked pepper adds a subtle heat that balances the sugar.
• 3 teaspoons minced garlic: Garlic mellows as it slow-cooks, providing a deep, nutty foundation.
• 1/2 cup reduced salt soy sauce: This gives you the umami punch without the overwhelming sodium levels.
• 1 inch ginger: Freshly grated ginger provides a bright, zingy zing that ground ginger simply cannot match.
• 1/3 cup light brown sugar: This provides the classic molasses-tinged sweetness that caramelizes beautifully.
• 1/4 cup water: Just enough liquid to help the sauce emulsify without thinning it out too much.
• 2 tbsp vegetable oil: This helps distribute the heat and prevents the cornstarch-coated beef from clumping.
• 1 tbsp sesame oil: Add this for an earthy, toasted aroma that makes the dish smell professional.
• 1 tbsp sesame seeds: These add a delicate crunch and a beautiful visual finish.

Step-by-Step Instructions

Slice the flank steak into thin strips, ensuring you cut across the grain. Then, dice those strips into bite-sized cubes and move them into a large mixing bowl.

Season your beef generously with salt and pepper. Toss the meat with the cornstarch, mixing thoroughly until every piece is evenly coated. This might look a little messy, but that powdery coating is what makes the magic happen later.

Drizzle the vegetable oil into the bottom of your slow cooker and layer the beef inside. Don’t worry if the pieces overlap; the slow cooker handles it.

Whisk together the garlic, grated ginger, brown sugar, sesame oil, soy sauce, and water. Pour this liquid gold over the beef and give everything a quick stir to make sure the steak is well-acquainted with the sauce.

Cook on HIGH for 2 1/2 hours or on LOW for 4 to 5 hours. Your kitchen will start smelling incredible around the two-hour mark! When the timer dings, stir the mixture one last time to incorporate the thickened sauce.

Garnish with a heavy sprinkle of sesame seeds and those bright green onions. Serve it immediately over a steaming bed of jasmine rice or rice noodles.

Expert Tips for Success

To make slicing the beef easier, place the steak in the freezer for 20 minutes before cutting. The slight firmness allows you to get those restaurant-thin ribbons without the meat sliding around. If your sauce feels too thick after cooking, whisk in a tablespoon of warm water at a time until it reaches your desired consistency. To prevent the beef from sticking, ensure the slow cooker insert is lightly greased or use a slow cooker liner for an even faster cleanup.

Variations & Substitutions

If you want to make this Keto-friendly, swap the brown sugar for a monk fruit gold sweetener and use Xanthan gum in place of cornstarch (use only 1/2 teaspoon of Xanthan gum). If you find yourself without flank steak, sirloin tip or even chicken thighs work beautifully here. For a spicy kick, toss in a teaspoon of red pepper flakes or a squeeze of Sriracha during the final stir.

Frequently Asked Questions

Recipe updated in 2026 to reflect the most accurate timing and additional insights.

Slow Cooker Mongolian Beef for Busy Moms

Lauren Bennett

Tender slices of beef slow-cooked in a sweet-savory Mongolian sauce made with soy sauce, brown sugar, garlic, and ginger. The meat becomes melt-in-your-mouth soft while soaking up rich, sticky flavors—perfect served over rice with a sprinkle of green onions.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 4 hours hrs

Total Time 4 hours hrs 20 minutes mins

Course Dinner, Main Course

Cuisine Chinese-American

Servings 4 servings

Calories 420 kcal

Equipment

• Slow Cooker
• Mixing Bowl
• Whisk
• Chef's Knife
• Cutting Board

Ingredients

  

• 1 pound flank steak
• 2-3 stalks green onion or scallion
• 1/4 cup cornstarch
• 1 tsp salt to taste
• 1 tsp black pepper to taste
• 3 teaspoons minced garlic
• 1/2 cup reduced salt soy sauce
• 1 inch ginger
• 1/3 cup light brown sugar
• 1/4 cup water
• 2 tbsp vegetable oil
• 1 tbsp sesame oil
• 1 tbsp sesame seeds

Instructions

 

• Slice the flank steak against the grain into thin strips, then into cubes.
• Toss the beef with salt, pepper, and cornstarch until fully coated.
• Place vegetable oil and beef into the slow cooker.
• Whisk garlic, ginger, brown sugar, sesame oil, soy sauce, and water together and pour over beef.
• Cook on High for 2.5 hours or Low for 4-5 hours.
• Stir well and garnish with sesame seeds and green onions before serving.

Notes

• Freeze the beef for 20 minutes before slicing to get perfect thin strips.
• If the sauce is too thick, whisk in a tablespoon of warm water.
• Use a slow cooker liner for the fastest possible cleanup.

Keyword easy dinner for kids, easy weeknight dinner, flank steak recipe, homemade takeout, slow cooker beef soup

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