Slow Cooker Mongolian Beef

Name: Slow Cooker Mongolian Beef
Prep time: 15 min
Cook time: 3 h
Total time: 3 h 15 min
Cuisine: Asian
Ingredients: 1 1/2 pounds flank steak, thinly sliced against the grain; 1/4 cup cornstarch; 1 tablespoon toasted sesame oil; 1 teaspoon minced garlic; 1 teaspoon minced ginger; 1/2 cup low sodium soy sauce; 1/3 cup brown sugar; 1/2 cup water; 1/2 cup green onions, sliced (for garnish)

There’s something deeply comforting about a pot of slow-cooked beef bathing in a glossy, caramelized sauce—aromas of toasted sesame and simmered brown sugar mingle with garlic and ginger, promising rich, savory-sweet bites. Each forkful offers tender, pull-apart beef with a delicate crust from the cornstarch, bright bursts from scallions, and a sauce that clings luxuriously to steamed rice or noodles. This recipe feels like a warm hug on a chilly evening and a crowd-pleaser for busy weeknights and casual gatherings alike.

Make it when you want a hands-off dinner that fills the house with nostalgia (takeout vibes, but better), or prepare it for a potluck where people will swoon over the flavor without you needing to babysit the stove. It’s especially perfect for fall and winter, but any time you crave comfort food with an Asian-inspired profile.

At a Glance

Prep Time: 15 minutes
Cook Time: 2–3 hours on HIGH or 4–5 hours on LOW
Total Time: 2 hours 15 minutes–5 hours 15 minutes (depending on setting)
Servings: 4
Difficulty Level: Easy — great for beginners and busy cooks

Nutrition Highlights
Below is an approximate nutritional breakdown per serving (recipe yields 4 servings). Values are estimated using standard food composition data (USDA FoodData Central) and rounded for clarity. Actual values will vary by brand and exact cuts/quantities used.

Calories: ~475–500 kcal
Protein: ~46 g
Carbohydrates: ~26 g
Fat: ~18 g
Sodium: ~1,100–1,300 mg

Notes:

Sodium is elevated primarily from the soy sauce. The CDC recommends limiting sodium intake to less than 2,300 mg per day for most adults; those with hypertension or other conditions may be advised to aim lower. Adjust soy sauce or use low-sodium/tamari to reduce sodium per serving.
These figures are estimates and should be used as a guideline. For precise tracking, enter the exact brands and weights into a nutrition calculator or food-tracking tool that references USDA or other government data.

Why You’ll Love It

Bold, addictive flavor: The balance of dark soy, caramelized brown sugar, and toasted sesame oil creates a deeply savory-sweet sauce that’s instantly craveable.
Effortless prep with big payoff: Minimal hands-on time—coat, mix, and let the slow cooker do the heavy lifting. Perfect for busy evenings or when you want dinner waiting.
Family- and guest-friendly: The glossy sauce and tender beef appeal to adults and kids alike, making it ideal for weeknights, casual dinner parties, or meal prep.
Comfort-food nostalgia: Reminiscent of restaurant-style Mongolian beef, but made at home with control over sweetness, sodium, and portion size.

How to Make Slow Cooker Mongolian Beef

Ingredients

1 1/2 pounds flank steak, thinly sliced against the grain
1/4 cup cornstarch
1 tablespoon toasted sesame oil
1 teaspoon minced garlic
1 teaspoon minced ginger
1/2 cup low sodium soy sauce
1/3 cup brown sugar
1/2 cup water
1/2 cup green onions, sliced (for garnish)

Optional ingredients and substitutions:

For gluten-free: use tamari or a gluten-free soy sauce substitute. Replace cornstarch with arrowroot powder (same amount).
For lower sodium: use reduced-sodium soy sauce or dilute with extra water and a splash of rice vinegar for balance.
For a richer sauce: add 1–2 teaspoons hoisin sauce or 1 tablespoon oyster sauce.
For a thicker sauce finish: optionally mix 1–2 teaspoons cornstarch with 1 tablespoon cold water and stir into the slow cooker in the last 10–15 minutes.

Method & Process

Prepare the beef: Thinly slice flank steak against the grain into bite-sized strips. Toss the flank steak with cornstarch in a mixing bowl until evenly coated. Shake off excess cornstarch so pieces are coated but not clumpy.
Layer in the slow cooker: Place the coated steak in a single layer (as much as will fit without overcrowding) in the slow cooker. If necessary, tuck pieces in gently—do not press or compact.
Add aromatics and sauce: Add sesame oil, minced garlic, minced ginger, soy sauce, brown sugar, and water to the slow cooker. Stir gently to combine and ensure the meat is mostly submerged in the sauce.
Cook low and slow: Cover and cook on HIGH for 2–3 hours or LOW for 4–5 hours until beef is very tender and easily shredded with a fork. Avoid lifting the lid frequently—each peek adds 10–15 minutes to the cook.
Finish and garnish: If you want a thicker sauce, mix 1–2 teaspoons cornstarch with 1 tablespoon cold water and stir into the cooker in the last 10–15 minutes. Stir in green onions just before serving to keep them bright and crisp.
Serve immediately over steamed rice, noodles, or a bed of sautéed vegetables.

Practical tips:

Slice against the grain to keep beef tender. Use a partially frozen steak for easier, cleaner slicing.
Avoid overmixing the coated beef before adding to the slow cooker—too much agitation can strip off the cornstarch coating, which helps create that silky sauce.
Check doneness early if using thinner slices—some cuts can become tender faster.
If sauce is too thin after cooking, remove the meat and thicken the sauce on the stove over medium heat with a cornstarch slurry.

Serving Suggestions

Classic: Serve over steamed jasmine or brown rice with a sprinkle of sesame seeds and extra sliced green onions.
Noodle bowl: Toss with udon, lo mein, or wide rice noodles and add steamed bok choy or broccoli.
Lighter: Serve over cauliflower rice and add extra steamed greens for a lower-carb option.
Crispy contrast: Pile the Mongolian beef atop crispy fried rice or alongside tempura vegetables for texture contrast.
Appetizer/snack: Serve small portions in crispy wonton cups or on skewers for party-style bites.

Storage Instructions

Room temperature: Do not store uncooked perishable ingredients at room temperature. Cooked Mongolian beef should not sit out longer than 2 hours.
Refrigerator: Store cooled leftovers in an airtight container for up to 3–4 days. Reheat gently on the stove or in the microwave until steaming.
Freezer: Freeze in airtight containers or heavy-duty freezer bags for up to 2–3 months. Thaw overnight in the refrigerator before reheating. For best texture, freeze the sauce and beef together; reheat slowly and add a splash of water if the sauce tightens.

Chef’s Advice

Best cuts: While flank steak is recommended for this recipe (lean and flavorful), skirt or hanger steak also work well if sliced thinly against the grain. Avoid very tough cuts without thin-slicing.
Texture balance: The cornstarch gives the beef a slightly crisp exterior that softens during cooking into a glossy coating—don’t skip it. If you prefer a softer finish, reduce cornstarch to 2 tablespoons.
Flavor depth: Toast the sesame oil briefly with the garlic and ginger in a small pan before adding to the slow cooker for a subtly deeper aroma.
Sauce control: If you prefer less sweetness, reduce brown sugar by 1–2 tablespoons and taste-adjust at the end. You can also add a splash of rice vinegar for brightness.

Creative Twists

Vegan/plant-based: Replace beef with thickly sliced king oyster mushrooms or extra-firm tofu (pressed and pan-seared). Use tamari and vegetable broth instead of water for depth.
Spicy kick: Add 1–2 teaspoons chili garlic sauce or a teaspoon of crushed red pepper flakes for heat. Finish with a drizzle of chili oil for aromatic spice.
Citrus-sesame: Stir in 1 tablespoon fresh orange juice and a teaspoon of grated orange zest for a tangy-sweet lift.
Veg-forward: Add sliced bell peppers, snap peas, and carrots in the last hour of cooking (or steam separately and combine at service) for color and nutrition.

Frequently Asked Questions
Q: Can I use a different cut of beef?
A: Yes—skirt, hanger, or sirloin can work. Slice thinly against the grain; adjust cook time slightly if using thinner cuts.

Q: My sauce is too thin—how do I thicken it?
A: Mix 1–2 teaspoons cornstarch with 1 tablespoon cold water to make a slurry. Stir into the slow cooker on HIGH for the last 10–15 minutes, or thicken on the stovetop after removing the meat.

Q: How can I reduce sodium without losing flavor?
A: Use low-sodium soy sauce or tamari, dilute with a bit more water, and boost umami with a teaspoon of mushroom powder or a splash of low-sodium Worcestershire sauce.

Q: Can I prepare this ahead of time for a party?
A: Yes—cook earlier in the day and keep on the slow cooker’s warm setting for a few hours. For longer holding, reheat gently from refrigerated storage before serving.

Q: Is this recipe freezer-friendly?
A: Yes—store in freezer-safe containers for up to 2–3 months. Thaw overnight in the fridge and reheat slowly to preserve texture.

Jump to Recipe Card

Conclusion

Slow Cooker Mongolian Beef transforms simple ingredients into a glossy, comfort-filled dish that’s perfect for weeknights, entertaining, or meal prep. Try it as written or use the variations to suit dietary needs and flavor preferences—and please share your results with the community.

For another trusted slow-cooker take, see Dinner at the Zoo’s Slow Cooker Mongolian Beef, and for an alternative recipe with helpful tips, check out The Chunky Chef’s Easy Slow Cooker Mongolian Beef Recipe.