Slow Cooker Mongolian Beef

Slow Cooker Mongolian Beef delivers the bold, sweet-savory flavors of your favorite takeout dish with minimal effort. Thinly sliced flank steak slowly simmers in a rich soy-brown sugar sauce until tender and glossy, creating a restaurant-style meal right at home. Finished with sesame oil, fresh carrots, and green onions, this dish is deeply flavorful and perfect served over rice or noodles.

Why You’ll Love This Recipe

• Better Than Takeout – Rich, glossy sauce and tender beef made easily at home.
• Hands-Off Cooking – The slow cooker does most of the work.
• Perfectly Tender Beef – Slow cooking breaks down fibers for melt-in-your-mouth texture.
• Balanced Sweet and Savory Sauce – Brown sugar and soy sauce create signature Mongolian flavor.
• Meal-Prep Friendly – Reheats beautifully for leftovers.
• Customizable Heat Level – Add or omit red pepper flakes to suit your taste.

Ingredients You’ll Need

For the Beef

• 2 pounds flank steak or top sirloin, thinly sliced against the grain – Ensures tenderness and quick cooking.
• 6 tablespoons cornstarch – Coats the beef and thickens the sauce into a glossy finish.
• 3 tablespoons vegetable or avocado oil (optional) – Adds richness and mouthfeel.

For the Sauce

• ¾ cup low-sodium soy sauce – Provides salty umami depth.
• ¾ cup packed brown sugar – Adds sweetness and caramel undertones.
• ¾ cup water – Balances salt and helps create sauce volume.
• 1½ tablespoons rice vinegar – Adds subtle acidity.
• 1½ tablespoons freshly grated ginger (or ½ teaspoon ground) – Contributes warmth and brightness.
• 1 tablespoon garlic, minced – Deepens savory flavor.
• ½ teaspoon crushed red pepper flakes (optional) – Adds gentle heat.

Finishing Ingredients

• 1 cup grated carrot (added in final 15–20 minutes) – Adds color and slight sweetness.
• 2 teaspoons sesame oil – Provides nutty aroma and authentic flavor.
• 1–2 teaspoons rice wine vinegar – Brightens and balances the finished sauce.
• 2 green onions, thinly sliced (for garnish) – Adds freshness.
• 1 tablespoon toasted sesame seeds (for garnish) – Provides texture and visual appeal.

Step-by-Step Instructions

Slice and Coat the Beef

Slice the steak thinly against the grain for maximum tenderness. Toss the beef with cornstarch in a mixing bowl until evenly coated.

Prepare the Sauce

In a separate bowl, whisk together soy sauce, brown sugar, water, rice vinegar, ginger, garlic, and red pepper flakes until fully combined.

Combine in Slow Cooker

Add the coated beef to the slow cooker. Pour the sauce over the beef and stir gently to coat. Drizzle in oil if using for added richness.

Slow Cook Until Tender

Cover and cook on Low for 4 hours or High for 2 hours, until the beef is tender and the sauce has thickened into a glossy consistency.

Add Final Ingredients

During the final 15–20 minutes of cooking, stir in grated carrot, sesame oil, and rice wine vinegar. Allow flavors to meld while carrots soften slightly.

Serve and Garnish

Serve hot over steamed rice or noodles. Garnish with sliced green onions and toasted sesame seeds. Add steamed broccoli on the side for a complete meal.

Recipe Notes & Tips

• Freeze Beef Briefly Before Slicing – Chilling for 15–20 minutes makes thin slicing easier.
• Always Slice Against the Grain – Prevents chewy texture.
• Do Not Skip Cornstarch – Essential for thick, glossy sauce.
• Add Vegetables at the End – Prevents overcooking and maintains texture.
• Use Low-Sodium Soy Sauce – Helps control overall saltiness.
• Adjust Sweetness – Reduce brown sugar slightly for a less sweet version.

Nutritional Information

• Prep Time: 15 minutes
• Cook Time: 4 hours
• Total Time: 4 hours 15 minutes
• Servings: 4–6 servings
• Calories: 684 kcal per serving (estimated)
• Carbohydrates: 59g
• Protein: 54g
• Fat: 25g
• Saturated Fat: 7g
• Sodium: 1886mg

Perfect Pairings

• Steamed Jasmine Rice – Absorbs the rich sauce beautifully.
• Lo Mein or Rice Noodles – A hearty alternative to rice.
• Steamed Broccoli or Snap Peas – Adds freshness and crunch.
• Chilled Cucumber Salad – Provides cooling contrast.

Ideal Occasions

• Busy Weeknight Dinners – Minimal hands-on time.
• Meal Prep Sessions – Stores and reheats well.
• Family Gatherings – Comforting and crowd-pleasing.
• Takeout-Inspired Nights – Satisfies cravings at home.

Storage & Serving Tips

• Refrigerate Promptly – Store in an airtight container for up to 4 days.
• Freeze for Later – Freeze up to 2 months; thaw overnight before reheating.
• Reheat Gently – Warm on stovetop with a splash of water to loosen sauce.
• Store Separately from Rice – Prevents rice from absorbing too much moisture.

Creative Variations to Try

• Add Bell Peppers – For extra color and sweetness.
• Use Honey Instead of Brown Sugar – Creates a slightly lighter sweetness.
• Make It Spicier – Increase red pepper flakes or add chili paste.
• Swap Protein – Try chicken thighs or tofu for variation.

Troubleshooting Common Issues

• Sauce Too Thin – Cook uncovered for the last 20 minutes or add a cornstarch slurry.
• Beef Too Tough – Ensure it’s sliced thinly against the grain and cooked long enough.
• Too Salty – Add a splash of water or a teaspoon of sugar to balance.
• Too Sweet – Add additional rice vinegar to brighten and cut sweetness.

Why This Recipe Works

This recipe works because it relies on proper slicing technique and controlled slow cooking. Cutting the beef against the grain shortens muscle fibers, resulting in tenderness. Cornstarch forms a coating that both protects the meat during cooking and thickens the sauce as it simmers. The combination of soy sauce and brown sugar creates a balanced sweet-savory base, while ginger and garlic add aromatic complexity. Finishing with sesame oil and rice vinegar enhances aroma and acidity, giving the dish its authentic takeout flavor. At 684 calories per serving, it offers a protein-rich, satisfying main course with bold flavor.

Final Thoughts

Slow Cooker Mongolian Beef is an easy, flavorful way to recreate a beloved restaurant dish at home. Its glossy sauce, tender beef, and balanced sweet-savory profile make it a dependable crowd-pleaser. While moderately high in sodium and calories, pairing it with steamed vegetables and controlling portion size creates a well-rounded, satisfying meal perfect for any night of the week.