If you’re craving a comforting, restaurant-quality meal with minimal effort, this Slow Cooker Mongolian Beef delivers every time. It’s rich, silky, sweet-savory, and effortlessly tender thanks to long, slow cooking. With only a few minutes of prep, the beef melts into a glossy sauce packed with garlic, ginger, and brown sugar perfect for spooning over fluffy rice or noodles. This recipe balances convenience with depth of flavor, making it a weeknight favorite that tastes like takeout but feels homemade.
Table of Contents
Slow Cooker Mongolian Beef Recipe
Prep Time:
10 minutes
Cook Time:
4 hours (LOW) or 2 hours (HIGH)
Total Time:
4 hours 10 minutes
Servings:
6
Calories:
365 per serving
Ingredients
- 2 lbs flank steak, thinly sliced against the grain
- 1/3 cup cornstarch
- 3/4 cup low-sodium soy sauce
- 1/2 cup brown sugar, packed
- 1/2 cup water
- 1/4 cup hoisin sauce
- 1 tbsp fresh ginger, grated
- 4 cloves garlic, minced
- 1 tsp sesame oil
- 1/2 tsp black pepper
- 1/4–1/2 tsp crushed red pepper flakes (optional)
- 1 cup sliced green onions (divided: half for cooking, half for garnish)
- 1 tbsp toasted sesame seeds (optional)
Instructions
- Place sliced flank steak in a large bowl and toss with cornstarch until evenly coated. Shake off excess.
- In the slow cooker, whisk together soy sauce, brown sugar, water, hoisin sauce, ginger, garlic, sesame oil, pepper, and red pepper flakes.
- Add the coated beef slices and half of the green onions. Stir gently to submerge.
- Cover and cook on LOW for 4–5 hours or HIGH for 2–2.5 hours, or until meat is tender.
- If the sauce needs thickening, stir in an additional 1 tablespoon cornstarch mixed with 1 tablespoon cold water. Cook 10–15 more minutes.
- Garnish with remaining green onions and sesame seeds before serving.
Substitutions & Dietary Swaps
This recipe is flexible and adapts well to personal needs. For a gluten-free version, swap soy sauce for tamari and confirm your hoisin is gluten-free. If you prefer lower sugar, reduce the brown sugar to 1/3 cup and increase the water by 2 tablespoons. Flank steak can be replaced with sirloin, skirt steak, or even thin-sliced chuck roast for a more budget-friendly option. To add vegetables, stir in matchstick carrots, broccoli florets, or snow peas during the last 30 minutes of cooking.
Chef’s Pro Tips
- Slice very thin: Place steak in the freezer for 20 minutes before slicing for cleaner cuts.
- Don’t skip cornstarch: It creates the signature glossy coating and thickens the sauce.
- Use low-sodium soy sauce: Slow cooking intensifies saltiness, so this keeps flavors balanced.
- Stir only once: Excessive stirring breaks the beef fibers and changes texture.
- Add aromatics early, veggies late: Ginger and garlic should simmer; vegetables should stay crisp-tender.
Make Ahead, Storage & Reheating
To prep ahead, slice beef and whisk the sauce ingredients up to 24 hours in advance. Store separately and combine when ready to cook. Leftovers keep 4 days refrigerated or up to 3 months frozen. Reheat gently on the stovetop over medium-low heat, adding a splash of water if the sauce thickens too much. If reheating from frozen, thaw overnight in the refrigerator for best texture.
Troubleshooting & Common Mistakes
- Beef is chewy: It was sliced too thick or undercooked. Allow more time on LOW.
- Sauce too thin: Add a cornstarch slurry (1:1 cornstarch to cold water).
- Sauce too salty: Add 1–2 tablespoons brown sugar or 1/4 cup water and simmer.
- Tastes flat: Add a splash of rice vinegar or fresh lime juice for brightness.
- Over-sweet: Balance with extra soy sauce and ginger.
Flavor Pairings & Serving Suggestions
Slow Cooker Mongolian Beef
Ingredients
Equipment
Method
- Place the thinly sliced flank steak in a large bowl and toss with the cornstarch until all pieces are lightly coated. Shake off any excess.
- In the slow cooker, whisk together the low-sodium soy sauce, brown sugar, water, hoisin sauce, grated ginger, minced garlic, sesame oil, black pepper, and crushed red pepper flakes (if using).
- Add the coated beef slices to the slow cooker along with half of the sliced green onions. Stir gently so the beef is submerged in the sauce.
- Cover and cook on LOW for 4–5 hours or on HIGH for 2–2.5 hours, until the beef is very tender.
- If you prefer a thicker sauce, whisk together 1 tablespoon cornstarch with 1 tablespoon cold water, stir it into the slow cooker, and cook for an additional 10–15 minutes.
- Serve the Mongolian beef over rice or noodles and garnish with the remaining green onions and toasted sesame seeds.
Notes
FAQs
Can I use chicken instead of beef? Yes! use boneless chicken thighs and reduce cook time by 30–45 minutes.
Can I prep this the night before? Absolutely. Store beef and sauce separately for best texture.
Does it freeze well? Yes. Freeze in airtight containers for up to 3 months.
Can I double the recipe? Yes, but increase cook time by about 30 minutes and use a larger slow cooker.
How do I keep the beef tender? Slice thinly, cook on LOW, and avoid over-mixing during cooking.
Can I add vegetables? Yes! add broccoli, carrots, or snow peas in the last 30 minutes.
Conclusion
This Slow Cooker Mongolian Beef brings effortless comfort, deep flavor, and weeknight convenience together in one dish. It’s tender, glossy, and irresistibly saucy everything a great slow cooker dinner should be. If you love easy, flavorful meals with takeout vibes, bookmark this recipe and explore more slow-cooked favorites across the site.