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Sweet, savory, garlicky, and loaded with deep umami flavor this Slow Cooker Mongolian Beef is everything you love about the restaurant classic made entirely at home in the crockpot. Thin strips of flank steak slow-cooked in a rich soy, brown sugar, and garlic sauce until fork-tender and perfectly glazed. This is the kind of better-than-takeout dinner that costs a fraction of the price and comes together with almost zero effort.
This easy Mongolian beef recipe is a crowd-pleaser every single time and one of the most requested slow cooker beef dinners you can make.
Why You Will Love This Recipe
- Rich, glossy sauce with the perfect balance of sweet and savory
- Fork-tender beef that melts in your mouth after slow cooking
- Better than takeout at a fraction of the cost
- Simple pantry ingredients with minimal prep
- Great for meal prep and even better as leftovers
Ingredients
| Ingredient | Quantity |
|---|---|
| Flank steak, sliced thin against the grain | 2 lbs |
| Low-sodium soy sauce | 1/2 cup |
| Brown sugar | 1/2 cup |
| Beef broth | 1/4 cup |
| Garlic cloves, minced | 5 cloves |
| Fresh ginger, grated | 1 tsp |
| Sesame oil | 1 tbsp |
| Red pepper flakes | 1/2 tsp |
| Cornstarch | 3 tbsp |
| Water | 3 tbsp |
| Green onions, sliced | For garnish |
| Toasted sesame seeds | For garnish |
Substitutions:
- Use sirloin or chuck steak as a budget-friendly alternative to flank steak
- Replace brown sugar with honey or coconut sugar
- Use tamari instead of soy sauce for a gluten-free version
Step by Step Instructions
Step 1: Coat the beef
Place the sliced flank steak in a zip-lock bag with the cornstarch and shake until all pieces are lightly coated. This helps the sauce thicken naturally during cooking.
Step 2: Make the sauce
In a bowl, whisk together soy sauce, brown sugar, beef broth, garlic, ginger, sesame oil, and red pepper flakes.
Step 3: Add to the crockpot
Place the coated beef in the slow cooker and pour the sauce over it. Toss lightly to coat all the pieces.
Step 4: Cook
Cover and cook on LOW for 4 to 5 hours or on HIGH for 2 to 3 hours.
Step 5: Thicken the sauce
Mix cornstarch and water in a small bowl. Stir the slurry into the crockpot and cook on HIGH uncovered for 15 to 20 minutes until the sauce thickens into a glossy glaze.
Step 6: Serve
Serve over steamed rice and garnish generously with sliced green onions and toasted sesame seeds.
Tips and Tricks
- Partially freeze the flank steak for 20 minutes before slicing it makes cutting thin strips against the grain much easier
- Coating the beef in cornstarch before cooking helps the sauce cling to every piece and thickens it naturally
- For a deeper caramelized flavor, reduce the sauce in a skillet over high heat for a few minutes after slow cooking
- A drizzle of extra sesame oil just before serving adds a beautiful nutty aroma
- Broccoli florets added in the last 30 minutes of cooking make this a complete one-pot meal
Serving Suggestions
- Over steamed jasmine or white rice the classic pairing
- With steamed broccoli for a complete takeout-style plate
- Over fried rice for maximum flavor impact
- In lettuce cups as a lighter low-carb option
- Over lo mein noodles for a noodle bowl variation
Mistakes to Avoid
- Cutting with the grain : always cut flank steak against the grain or the beef will be tough and chewy no matter how long it cooks.
- Skipping the cornstarch coating : it is the key to a thick, glossy sauce that clings to the beef rather than pooling at the bottom.
- Using regular soy sauce : the sodium level becomes overwhelming. Always use low-sodium soy sauce in this recipe.
- Cooking on HIGH the entire time : LOW heat produces more tender, evenly cooked beef. HIGH is only for the final thickening step.
- Not garnishing with green onions : they add a fresh bite that perfectly balances the richness of the sauce.
Nutrition
| Nutrient | Per Serving (approx.) |
|---|---|
| Calories | 420 kcal |
| Protein | 40 g |
| Total Fat | 12 g |
| Saturated Fat | 3 g |
| Carbohydrates | 35 g |
| Fiber | 0 g |
| Sugar | 28 g |
| Sodium | 680 mg |
Based on 5 servings, not including rice. Values are estimates.
FAQ
What cut of beef works best for Mongolian beef?
Flank steak is the most popular choice because it slices thin and becomes incredibly tender in the slow cooker. Sirloin and chuck steak are good budget alternatives.
Can I make this gluten-free?
Yes. Use tamari or coconut aminos in place of soy sauce and ensure your beef broth is gluten-free certified.
Is Mongolian beef actually from Mongolia?
Despite the name, Mongolian beef is a Chinese-American dish that originated in Taiwan. It has no historical connection to Mongolian cuisine.
How do I store leftovers?
Store in an airtight container in the refrigerator for up to 4 days. Reheat on the stovetop over medium heat with a splash of broth to loosen the sauce.
Can I freeze this recipe?
Yes. Freeze without rice for up to 3 months. Thaw overnight in the refrigerator and reheat on the stovetop.
Recipe Card
| Prep Time | 10 minutes |
| Cook Time | 4 to 5 hours on LOW |
| Total Time | Approximately 4 hours 10 minutes |
| Servings | 4 to 5 |
| Calories | 420 kcal per serving |
| Course | Dinner |
| Cuisine | Chinese-American |
| Focus Keyword | slow cooker mongolian beef |
| Related Keywords | crockpot mongolian beef, easy mongolian beef recipe, flank steak slow cooker |
Make This Tonight
This Slow Cooker Mongolian Beef proves that the best takeout is the kind you make at home. Rich, glossy sauce, fork-tender beef, and a recipe so simple it practically makes itself. Once your family tastes this, the takeout app stays closed.
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