Mongolian Beef Slow Cooker

The first time I made Mongolian beef in a slow cooker, I honestly did not expect much. I tossed everything in before work, came home to the most incredible smell, and took one bite that completely changed my mind about slow cooker Asian dishes. My husband actually asked if I had ordered takeout and was trying to pass it off as homemade.

I served this at a small dinner party last winter when my friend Sarah was going through a tough divorce. She showed up looking exhausted and left asking for the recipe, saying it was the first time she had felt genuinely comforted by food in months. There is something about that combination of salty, sweet, and umami that just wraps around you like a warm blanket.

Ingredients

• Flank steak: Thinly slicing against the grain is the secret to tender beef, even after long cooking
• Cornstarch coating: This creates a velveting effect that protects the meat and helps thicken the sauce naturally
• Low sodium soy sauce: Regular soy sauce makes this dish far too salty, trust me on this one
• Dark brown sugar: The molasses content gives the sauce that gorgeous caramel color and depth
• Hoisin sauce: This is the flavor backbone, bringing fermented bean sweetness and complexity
• Fresh ginger and garlic: Do not use powdered versions here, the fresh aromatics are non negotiable
• Green onions: Separating white and green parts lets you layer flavors at different stages
• Toasted sesame seeds: These add a nutty crunch that makes every bite interesting

Instructions

Prepare the beef:

Toss the thinly sliced flank steak with cornstarch until every piece is lightly dusted, then shake off any excess coating. This step might feel fussy but it makes all the difference in texture.

Layer the meat:

Add the coated beef to your slow cooker, spreading it into an even layer so everything cooks at the same rate.

Whisk the sauce:

In a separate bowl, combine soy sauce, brown sugar, water, hoisin, sesame oil, ginger, garlic, black pepper, and red pepper flakes until the sugar completely dissolves. I use a whisk and give it about 30 seconds of serious attention.

Combine everything:

Pour the sauce over the beef and toss gently with tongs to coat each piece. Scatter the white parts of the green onions on top, letting them perfume the dish as it cooks.

Let it cook:

Cover and cook on low for 4 hours. The beef should be fork tender and the sauce will have thickened beautifully on its own.

Add the finishing touch:

Stir in the sliced green onion tops and let everything cook for 10 more minutes. This brightens the flavor and adds fresh color to the dish.

Serve it up:

Spoon the beef and sauce over steamed rice, then finish with toasted sesame seeds and extra green onions if you want it to look as good as it tastes.

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This recipe has become my go to when I need to feed a crowd without disappearing into the kitchen for hours. Last summer my brother came to visit with three hungry teenage boys, and they literally hovered around the slow cooker, eating it straight from the pot with forks.

Make It Your Own

I love adding sliced bell peppers or snap peas during the last hour of cooking when I want more color and nutrition. The vegetables stay crisp tender and soak up all that incredible sauce while maintaining their fresh crunch.

Perfect Pairings

Steamed broccoli is my number one side, with its florets catching all that sauce. Sautéed bok choy works beautifully too, adding a bitter note that balances the sweet and salty flavors perfectly.

Meal Prep Success

This beef actually tastes better the next day, making it ideal for batch cooking. I always make a double batch and portion it into glass containers for lunch throughout the week. The sauce continues to develop and the beef becomes even more tender as it sits.

• Cool the food completely before refrigerating to prevent condensation from watering down the sauce
• Store rice separately and recombine when heating to maintain the best texture
• The beef freezes beautifully for up to three months if you want to stock your freezer

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There is something deeply satisfying about coming home to a meal that has been cooking all day, waiting for you. This Mongolian beef turns an ordinary Tuesday into something worth celebrating.

Common Recipe Questions

→ What cut of beef works best for this dish?

Flank steak is ideal as it becomes incredibly tender when slow-cooked. The key is to slice it thinly against the grain, which helps break down the muscle fibers and ensures tenderness. You can also use sirloin or skirt steak as alternatives.

→ Can I make this gluten-free?

Yes, simply substitute tamari for soy sauce and ensure your hoisin sauce is gluten-free. The cornstarch thickener can be replaced with arrowroot powder or tapioca starch for a gluten-free version.

→ How do I prevent the beef from becoming tough?

The secret is slicing against the grain and using a slow cooker on low heat for 4 hours. This gentle cooking method breaks down the tough fibers in flank steak, resulting in melt-in-your-mouth tenderness. Don't rush the cooking time!

→ What vegetables pair well with this dish?

Steamed broccoli, sautéed bok choy, or stir-fried snap peas complement the rich flavors perfectly. Add them in the last hour of cooking if using the slow cooker, or serve alongside for a balanced meal.

→ Can I make this ahead of time?

Absolutely! The flavors actually improve when made ahead. You can refrigerate for 2-3 days or freeze for up to a month. Reheat gently on the stovetop or in the microwave, adding a splash of water if needed to restore the sauce consistency.