Slow Cooker Mongolian Beef

If you’re looking to skip takeout but still crave that classic favorite, this slow cooker Mongolian beef recipe will quickly become your go-to on busy nights. Tender strips of flank steak slowly cook in a rich garlic-ginger soy sauce that’s both sweet and savory, creating melt-in-your-mouth goodness. And here’s the best part: your slow cooker does all the hard work while filling your kitchen with an amazing aroma that signals delicious dinner is on the way.

This recipe captures everything you love about restaurant-style Mongolian beef—the sticky sauce, bold flavors, and just the right amount of sweetness—but simplifies it for the slow cooker. Just a quick mix in the morning sets you up for an easy dinner with no wok or last-minute fuss. Serve it piled high over steamed rice and garnish with sesame seeds for a cozy dinner that beats takeout every time.

What Makes It So Good

Tender, restaurant-quality beef: Thin flank steak slices cook slowly so every bite is juicy and melts in your mouth.

Sticky, glossy sauce: Cornstarch thickens the sauce into that silky, shiny texture that Mongolian beef is famously loved for, balancing sweet and savory perfectly. For a crisp, tangy contrast that cuts through the richness, top your bowl with quick fridge pickled vegetables.

Effortless cooking: Just a few minutes to prep, then let your slow cooker do the heavy lifting—ideal for hectic weeknights. If you love set-and-forget comfort food, you might also enjoy Crock Pot Chicken Pot Pie.

Family-friendly flavor: The combination of garlic, fresh ginger, and soy sauce delivers tasty, bold flavors that everyone at the table will ask for again.

What You Need to Gather

• 2 pounds flank steak or top sirloin, thinly sliced against the grain
• 6 tablespoons cornstarch
• 3 tablespoons vegetable or avocado oil (optional, adds richness)
• 3/4 cup low-sodium soy sauce
• 3/4 cup brown sugar, packed
• 3/4 cup water
• 1 1/2 tablespoons rice vinegar
• 1 1/2 tablespoons freshly grated ginger (or 1/2 teaspoon ground ginger)
• 1 tablespoon garlic, minced
• 1/2 teaspoon crushed red pepper flakes (optional)
• 1 cup grated carrot (added in last 15 minutes)
• 2 teaspoons sesame oil
• 1-2 teaspoons rice wine vinegar
• 2 green onions, thinly sliced (for garnish)
• 1 tablespoon sesame seeds, toasted (for garnish)

How to Make It

1. (Optional) Chill steak in the freezer about 20 minutes to firm for easier thin slicing.
2. Slice the steak very thin against the grain.
3. Toss the sliced steak with cornstarch until each piece is evenly coated.
4. Whisk together soy sauce, brown sugar, water, rice vinegar, grated ginger, minced garlic, and crushed red pepper flakes (if using).
5. (Optional) Quickly sear the cornstarch-coated beef in a hot skillet for a minute or two per side for crisp edges.
6. Place the coated beef in the slow cooker, pour the sauce over the beef, stir gently to coat, and drizzle in oil if using.

7. Cover and cook on Low for 4 hours or on High for 2 hours, until the beef is tender and the sauce thickens.

   

8. About 15 minutes before the end of cooking, stir in the grated carrot, sesame oil, and rice vinegar.
9. (Optional) If you want a thicker glossy sauce, whisk 1 tablespoon cornstarch with 2 tablespoons cold water and stir the slurry into the slow cooker during the last 15 minutes.

Pro Tips for Success

• Slice the beef very thin: For best texture, cut across the grain. Freeze the meat for about 20 minutes before slicing to make this a breeze.
• Don’t skip the cornstarch: This coats the meat and thickens the sauce so you get that perfect, luscious finish.
• Add veggies late: Stir in the carrots near the end of cooking so they keep a little bite and vibrant color.
• Pick your cooking time: Go with High for 2–3 hours if you’re short on time, or Low for 4–5 hours when you want a true slow-cooked melt-in-your-mouth result.

• Brighten up at the end: Mixing sesame oil and rice vinegar in right before serving lifts the dish with fresh, tangy notes.

Mix-Ins and Substitutions

Here are some simple ways to tweak this slow cooker Mongolian beef recipe so it suits what you have on hand or your taste preferences:

• Try different proteins: Skirt steak or thin sirloin are great swaps. Boneless chicken thighs work well too—cook Low 3–4 hours or High 2 hours, then cut into strips. Pork tenderloin can be used, just watch cooking time closely. For a vegetarian twist, use extra-firm tofu: press, cube, dust with cornstarch, pan-fry until golden, then add to the sauce in the last 20–30 minutes so it soaks flavors without falling apart.
• Add different veggies: Broccoli, bell peppers, snap peas, mushrooms, or baby bok choy are all tasty options. Add these in the final 15–30 minutes so they stay crisp-tender—the carrots already suggested help with this.
• Swap sauces: Use tamari or coconut aminos instead of soy sauce for gluten-free or lower sodium options. Switch brown sugar for honey or maple syrup if you want a different sweetness—just adjust the amount to taste. Stir in 1–2 teaspoons of hoisin sauce for a richer, deeper flavor.
• Spice it up: Crank up the heat with an extra ½–1 teaspoon of crushed red pepper flakes, a squirt of Sriracha, or a tablespoon of gochujang added to the sauce.
• Get crispy edges: For a little crispness, toss the cornstarch-coated beef quickly in a hot skillet before slow cooking or broil the finished beef on a baking sheet for 2–3 minutes to caramelize.
• Serving swaps: Try serving over cauliflower rice, or your favorite udon or lo mein noodles, or spoon it into crisp lettuce cups (see Beef San Choy Bao (Chinese Lettuce Cups) for how to prep the leaves). You can also pile it on stir-fried veggies instead of plain rice.
• Lower sugar/keto-friendly: Swap brown sugar with a granular sweetener like erythritol or monk fruit. Adjust water quantity slightly to keep the sauce nice and glossy.

Storing, Freezing, and Reheating

Storing

• Keep leftovers in an airtight container in your fridge for up to 4 days. The sauce will thicken as it cools but loosens right back up when reheated.

Reheating

• For bigger batches, cover with foil and warm in a 350°F oven for 15–20 minutes.
• If you’re using glass or ceramic bakeware, bring it to room temp first to avoid cracking when heated.
• For quick meals, warm single servings gently on the stove or in the microwave.

Freezing

• This Mongolian beef freezes beautifully. Let it cool completely, then pack it in a freezer-safe container or bag. Freeze for up to 3 months. Thaw overnight in the fridge before reheating.

Make-Ahead

• For easy prep, slice the beef and mix the sauce the night before. Keep them separate in the fridge and combine in the slow cooker when you’re ready. You can even cook the whole dish a day early—flavors deepen wonderfully with a little rest! If you’re building a make-ahead menu, our French Onion Beef Casserole also reheats beautifully.

Frequently Asked Questions

Can I use a different cut of beef?
Definitely! Flank steak is the traditional choice, but skirt steak or thin sirloin slices work just as well. Just be sure to slice against the grain for maximum tenderness.

Do I have to use a slow cooker?
Nope. You can make this on the stovetop by simmering the beef in the sauce for 20–25 minutes until tender. Add the carrots, sesame oil, and rice vinegar right at the end.

Can I make this ahead of time?
Absolutely. You can slice the beef and mix sauce ingredients the night before. Store separately in the fridge, then combine and cook the next day.

Can I freeze Mongolian beef?
Yes! This recipe freezes wonderfully. Store cooled leftovers in an airtight container for up to 3 months. Thaw overnight in the fridge and warm gently before eating.

Is this recipe spicy?
As is, it’s mild. If you want heat, just add ½–1 teaspoon crushed red pepper flakes or a sliced chili while cooking.

💡 Pro Tip: Want a thicker sauce? Whisk 1 tablespoon cornstarch with 2 tablespoons cold water and stir it into the slow cooker during the last 15 minutes. This gives you that beautiful glossy, restaurant-style finish.