Slow Cooker Mongolian Beef – Easy Crock Pot Mongolian Beef Recipe

If you’re looking for a fuss-free, restaurant-style dish that practically cooks itself, this Slow Cooker Mongolian Beef is the answer. Rich, savory, and slightly sweet, this takeout-inspired favorite is made effortless with the help of your crock pot.

Thinly sliced flank steak simmers low and slow in a sticky sauce made with soy, garlic, ginger, and brown sugar, resulting in melt-in-your-mouth tenderness and bold flavor in every bite. Served over rice or noodles, it’s the ultimate weeknight comfort meal — with barely any prep and maximum flavor payoff.

This slow cooker version takes all the flavor of traditional Mongolian beef and adapts it into an easy, make-ahead dish that tastes even better than takeout.

Ingredients Overview

Main Ingredients

• Flank Steak: This lean cut becomes incredibly tender when cooked low and slow. Slice it thinly against the grain for the best texture.

• Cornstarch: Tossing the beef in cornstarch gives the sauce its signature silky thickness and helps create that glossy, restaurant-style coating.

• Soy Sauce: Use low-sodium soy sauce to control salt levels while still packing in rich umami flavor.

• Brown Sugar: Adds a hint of sweetness and helps caramelize the sauce as it simmers.

• Garlic & Ginger: Freshly minced or grated for bold, aromatic depth. These are essential to authentic Mongolian flavor.

• Beef Broth: Helps thin the sauce while deepening the savory flavor profile.

• Sesame Oil: Just a small amount adds rich, nutty aroma — don’t skip it.

• Green Onions: Added at the end for freshness, crunch, and a mild onion bite.

Optional Additions

• Red Pepper Flakes: For a bit of heat.

• Hoisin Sauce: Adds extra depth and sweetness, similar to what’s used in some restaurant versions.

• Broccoli or Snow Peas: Stir in veggies at the end to turn this into a full one-pot meal.

• Sesame Seeds: A final garnish for texture and presentation.

Step-by-Step Instructions

1. Slice the Beef
   Trim any excess fat and slice the flank steak thinly against the grain. Aim for pieces about ¼-inch thick and 2 inches long for best results.

2. Coat with Cornstarch
   In a large bowl or zip-top bag, toss the beef with cornstarch until fully coated. Let it sit for 10 minutes — this helps the coating stick and thickens the sauce later.

3. Make the Sauce
   In a bowl or directly in the slow cooker, mix soy sauce, brown sugar, beef broth, minced garlic, ginger, and sesame oil. Stir until the sugar dissolves.

4. Combine in Slow Cooker
   Add the cornstarch-coated beef to the crock pot and pour the sauce over it. Stir gently to coat the beef evenly.

5. Cook Low and Slow
   Cover and cook on low for 4–5 hours or high for 2.5–3 hours, until the beef is tender and the sauce is thick and glossy.

6. Finish with Green Onions
   In the last 15–30 minutes of cooking, stir in sliced green onions. If you’re adding quick-cook veggies (like snow peas or broccoli), now’s the time.

7. Serve
   Spoon over steamed jasmine rice or lo mein noodles. Garnish with extra green onions and sesame seeds if desired.

Pro Tips

• Slice thinly and uniformly to ensure even cooking and tenderness.

• Don’t skip cornstarch — it’s what creates the signature texture.

• Use fresh garlic and ginger for maximum flavor — powders won’t give the same aromatic punch.

• Avoid overcooking — beef can become stringy if left too long in the crock pot, even on low.

Tips, Variations & Substitutions

• Low-Carb/Keto Version: Replace brown sugar with a keto-friendly sweetener (like monk fruit), and use coconut aminos instead of soy sauce.

• Spicy Version: Add 1 tsp red pepper flakes or a drizzle of sriracha to the sauce for a kick.

• Add Veggies: Stir in steamed broccoli, snap peas, bell peppers, or carrots toward the end for a built-in side dish.

• Gluten-Free Adaptation: Use tamari or certified gluten-free soy sauce.

• Beef Substitutions: While flank steak is ideal, you can use sirloin, skirt steak, or even thinly sliced chuck roast.

Serving Ideas & Occasions

This Slow Cooker Mongolian Beef is ideal for:

• Weeknight Dinners: Just prep in the morning and come home to a complete meal.

• Meal Prep: Make a double batch and portion it with rice for grab-and-go lunches.

• Family Gatherings: A crowd-pleaser that’s easy to multiply.

• Serve With:

  • Steamed rice or fried rice

  • Rice noodles or ramen

  • Steamed vegetables

  • Kimchi or quick cucumber salad for contrast

Add a drizzle of chili oil or a squeeze of lime to brighten the flavors.

Nutritional & Health Notes

This dish is packed with protein and rich in flavor, making it satisfying with relatively few ingredients. While the brown sugar adds some sweetness, it can be adjusted to taste or replaced with a natural alternative.

• Protein: Flank steak is lean yet rich in iron and B12.

• Carbs: Primarily from the sauce. Use less sugar for a lighter version.

• Fats: Minimal added fat — just a bit of sesame oil.

• Portion Control: Serve with lots of vegetables or cauliflower rice for a balanced plate.

FAQs

Q1: Can I use frozen beef?

Yes, but thaw it completely before slicing and coating. Frozen meat is harder to cut thinly and won’t absorb flavor as well.

Q2: Do I have to brown the beef first?

No browning is needed in this slow cooker version — the sauce and cornstarch take care of flavor and texture. But searing can add an extra layer of flavor if you have time.

Q3: Can I use a different cut of beef?

Yes — sirloin, skirt steak, or even thinly sliced chuck roast work well. Avoid stew meat or thick roasts unless pre-sliced.

Q4: Is this dish freezer-friendly?

Yes! Let the cooked beef cool completely, then freeze in portions for up to 2 months. Reheat gently in a pan or microwave with a splash of water to loosen the sauce.

Q5: Can I cook it longer?

It’s best not to exceed 6 hours on low. Overcooking can cause the beef to break down too much and become stringy.

Q6: How do I make the sauce thicker?

If your sauce isn’t thick enough, make a quick slurry (1 tbsp cornstarch + 2 tbsp cold water) and stir it into the slow cooker during the last 30 minutes on high.

Q7: What’s the difference between Mongolian Beef and Teriyaki Beef?

Mongolian beef has a deeper, more savory flavor with garlic, ginger, and soy, while teriyaki tends to be sweeter and includes mirin or sake. The textures and cooking methods can overlap, but the sauces differ.

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