Slow Cooker Mongolian Beef

This Slow Cooker Mongolian Beef is the recipe I reach for every time I want the bold flavors of my favorite Chinese restaurant without ever leaving home. Tender strips of flank steak simmered low and slow in a rich, sweet-savory sauce — it honestly could not be easier. I still remember the first time I made a version of this in my Midwest kitchen on a cold Tuesday evening, the kind of night when you just need something warm, fragrant, and satisfying waiting for you after a long day.

Growing up, my grandmother’s farmhouse kitchen always had something bubbling on the stove. The moment I dropped everything into the slow cooker and caught that first whiff of sesame, garlic, and ginger, I was taken right back to her table. This Slow Cooker Mongolian Beef has that same cozy, stick-to-your-ribs quality — the kind of meal that gathers everyone around and has them asking for seconds before the first plate is done. The sauce is deep, slightly sweet, perfectly savory, and clings to every piece of that silky beef in the most wonderful way. Your kitchen is about to smell incredible!

Why This Slow Cooker Mongolian Beef Belongs in Your Recipe Box

I have been making this recipe for years, and every single time it earns a spot on the weekly dinner rotation. The beauty of a great slow cooker meal is that it respects your time — and this one delivers bold, restaurant-style flavor with almost no effort on your part.

• Set it and forget it: Add everything to the slow cooker, cover, and walk away — dinner practically makes itself while you go about your day.
• Bold, crowd-pleasing flavor: The combination of soy sauce, brown sugar, garlic, sesame oil, and ginger creates a sauce that tastes like it took all day — because, well, it did.
• Uses pantry staples: Chances are you already have most of these ingredients on hand, making it a reliable weeknight go-to.
• Lean and satisfying: Flank steak is one of the leaner cuts of beef, so you get all the flavor without feeling weighed down.
• Meal prep friendly: This recipe makes enough for four generous servings and keeps beautifully in the fridge or freezer for days to come.
• Endlessly versatile: Serve it over rice, toss it with noodles, or scoop it into lettuce cups — it works every single way.

Key Players in This Recipe

Every ingredient in this Slow Cooker Mongolian Beef earns its place. Here is what goes in and why it matters:

Flank steak: This is my preferred cut for this recipe because it is lean, flavorful, and becomes wonderfully tender after a few hours in the slow cooker. I always slice it against the grain into thin strips — that single step makes a huge difference in the final texture.

Cornstarch: Coating the beef in cornstarch before cooking serves two important purposes: it helps the sauce cling to every piece of meat, and it gently thickens the sauce as everything cooks together. Do not skip this step.

Toasted sesame oil: In my kitchen, I always reach for toasted sesame oil rather than plain — it carries that deep, nutty aroma that makes the whole dish smell just like your favorite takeout spot.

Low sodium soy sauce: I learned early on that regular soy sauce makes the dish far too salty. Low sodium gives you that essential umami depth while keeping the flavors balanced and approachable.

Brown sugar: This is what gives the sauce its signature sweet edge and that beautiful glossy finish. Feel free to reduce the amount slightly if you prefer a more savory profile.

Fresh garlic and ginger: I always reach for fresh here — pre-minced works in a pinch, but fresh garlic and ginger bring a brightness and vibrancy that really sets this dish apart.

Green onions: Stirred in right at the end, they add a fresh, slightly sharp contrast to the rich sauce and give the dish that finishing pop of color.

How to Make Slow Cooker Mongolian Beef

Through years of making this dish, I’ve dialed in every step so you get perfect results every time. Here is my tested method:

1. Slice and coat the beef: Place your thinly sliced flank steak into a mixing bowl and add the cornstarch. I’ve found that tossing it thoroughly — really working the cornstarch into every piece — makes a noticeable difference in how the sauce coats the beef later.
2. Build your slow cooker: Transfer the coated beef into your slow cooker, then pour the sesame oil, minced garlic, minced ginger, soy sauce, brown sugar, and water directly over the meat. Stir gently so every strip gets coated in that gorgeous sauce.
3. Cook low and slow: Cover with the lid and cook on HIGH for 2–3 hours or LOW for 4–5 hours. After years of making this, I prefer the LOW setting when I have the time — the beef comes out just a touch more tender and the flavors deepen beautifully.
4. Finish with green onions: Right before serving, stir in the green onions. Adding them at this stage keeps them fresh and bright, which I love as a contrast to the richness of the sauce.
5. Rest and serve: Let the dish sit for a couple of minutes before serving — this allows the sauce to settle and the flavors to meld. Then spoon generously over your choice of rice or noodles and enjoy!

Tips for the Best Results

• Always slice the flank steak against the grain and as thin as you can manage — this is the single biggest factor in achieving tender, melt-in-your-mouth beef.
• Do not overcook on HIGH — sticking to the 2–3 hour window on HIGH prevents the beef from drying out.
• Want a little heat? Stir in a pinch of red pepper flakes or a spoonful of chili paste when you add the sauce ingredients.
• For extra vegetables, add sliced bell peppers, broccoli florets, or snap peas during the last 30 minutes of cooking.
• For a gluten-free version, simply swap in certified gluten-free soy sauce and cornstarch.

Making the Most of Leftovers

One of the things I love most about this Slow Cooker Mongolian Beef is that it is just as good the next day — maybe even better, because the sauce continues to develop overnight. I typically store leftovers in a tightly sealed airtight container in the refrigerator for up to 3–4 days. The beef stays tender and the sauce does not separate, which makes it perfect for packing lunches or a quick weeknight reheat.

This recipe also freezes beautifully, which is why I often make a double batch just for the freezer. Let the beef cool completely, then portion it into freezer-safe bags or containers. It keeps well for up to 2–3 months. When I’m planning ahead for busy weeks, having a container of this in the freezer feels like having a homemade meal on standby.

For reheating, my preferred method is on the stovetop over medium-low heat with a small splash of water stirred in to loosen the sauce — it comes back to life perfectly. If you’re short on time, the microwave works well too: cover your dish and heat in 1-minute intervals, stirring between each one. For the oven, preheat to 350°F, cover tightly with foil, and heat for about 20 minutes until warmed through.

Perfect Partners for Slow Cooker Mongolian Beef

A great main dish deserves great company. Here are my favorite ways to round out the plate:

• Steamed Jasmine Rice: The classic choice — its light, fragrant texture soaks up every drop of that incredible sauce.
• Lo Mein or Udon Noodles: Toss the beef and sauce straight into a bowl of noodles for a hearty, slurpable dinner the whole family will love.
• Crisp Lettuce Wraps: For a lighter, fun option — spoon the beef into butter lettuce cups and top with toasted sesame seeds for a fresh, hands-on meal.
• Roasted Broccoli: The slight char and nuttiness of oven-roasted broccoli is a wonderful counterpoint to the sweet-savory sauce.
• Sautéed Bok Choy: A quick stir-fry with garlic and a splash of soy sauce makes for a nutritious, flavor-harmonious side.
• Cucumber Salad: A cool, lightly dressed cucumber salad cuts right through the richness of the beef and refreshes the palate beautifully.

FAQs

Slow Cooker Mongolian Beef

Tender flank steak simmered in a sweet-savory garlic ginger sauce — this Slow Cooker Mongolian Beef tastes just like your favorite Chinese takeout, made effortlessly at home in your crock pot.

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 3 hours hrs

Total Time 3 hours hrs 15 minutes mins

Servings: 4 portions

Course: Dinner, Main Course

Cuisine: American, Asian

Calories: 350

Ingredients Equipment Method Notes

Ingredients

  

• 1.5 lbs flank steak thinly sliced against the grain
• 0.25 cup cornstarch
• 1 tbsp toasted sesame oil
• 1 tsp minced garlic fresh preferred
• 1 tsp minced ginger fresh preferred
• 0.5 cup low sodium soy sauce
• 0.33 cup brown sugar
• 0.5 cup water
• 0.5 cup green onions cut into 1/2-inch pieces, for garnish

Equipment

• Slow cooker (4-6 quart)
• cutting board
• sharp knife
• mixing bowl
• Measuring cups and spoons

Method

 

1. Place the thinly sliced flank steak in a mixing bowl with the cornstarch. Toss thoroughly until every piece is evenly coated.
2. Transfer the coated beef to your slow cooker. Pour the sesame oil, minced garlic, minced ginger, soy sauce, brown sugar, and water over the meat. Stir gently to combine.
3. Cover with the lid and cook on HIGH for 2-3 hours or LOW for 4-5 hours, until the beef is tender.
4. Stir in the green onions just before serving. Let the dish rest for a couple of minutes, then serve over steamed rice or noodles.

Notes

For best results, slice the flank steak against the grain as thin as possible. Do not skip the cornstarch coating. Use low sodium soy sauce to avoid an overly salty dish. For gluten-free, use certified gluten-free soy sauce and cornstarch. Add heat with red pepper flakes or chili garlic paste if desired.