Slow-Cooker Mongolian Beef has always been a go-to recipe in my kitchen, especially during those busy weeknights. It’s one of those dishes that feels fancy but is actually incredibly easy to make.
It is perfect for a cozy dinner at home, and I find it’s always a crowd-pleaser.
What I love most is how the slow cooker does all the work, leaving you with tender, flavorful beef in a rich, savory sauce.
Recipe Overview: Slow-Cooker Mongolian Beef
This dish is all about tender slices of beef coated in a sweet and savory sauce. Think of it as a takeout favorite, but made healthier and simpler right in your own kitchen.
The sauce has a delicious balance of soy sauce, brown sugar, and ginger. It gives the beef a wonderful flavor that just gets better as it simmers in the slow cooker.
It’s a meal that truly satisfies without requiring hours in the kitchen. I especially enjoy how the aroma fills the house while it cooks!
I often serve this Mongolian beef over fluffy white rice, but it’s also great with noodles or even in lettuce wraps for a lighter option.
It’s a flexible dish that fits right into any meal plan.
Ingredients for Mongolian Beef
Here’s what you’ll need to make this delicious dish:
- 1 ½ pounds flank steak, thinly sliced against the grain
- ¼ cup cornstarch
- 2 tablespoons olive oil
- ½ cup soy sauce (low sodium is best)
- ½ cup water
- ¾ cup brown sugar, packed
- 1 tablespoon minced garlic (about 3 cloves)
- 1 teaspoon ground ginger
- ¼ teaspoon red pepper flakes (optional, for a little heat)
- Green onions, sliced (for garnish)
- Sesame seeds (for garnish)
A note on the steak: Flank steak works really well because it gets super tender in the slow cooker. You can sometimes find it pre-sliced, which saves a bit of time! If you can’t find flank steak, sirloin steak is a good substitute.
For the soy sauce, I always recommend low-sodium. It lets you control the saltiness of the dish better.
And don’t skip the brown sugar – it’s what gives the sauce that signature sweetness and helps it thicken up nicely.
Step-by-Step Instructions: Making the Perfect Mongolian Beef
- Prepare the Beef: First, take your flank steak and slice it thinly against the grain. This helps make it extra tender. Then, put the sliced beef in a large zip-top bag or bowl and add the cornstarch. Toss it all together until the beef is evenly coated. This helps to thicken the sauce later.
- Sear the Beef (Optional but Recommended): Heat the olive oil in a large skillet over medium-high heat. Add the beef and sear it for about 2-3 minutes per side, just until it’s browned. You don’t need to cook it all the way through. This step adds extra flavor, but you can skip it if you’re short on time.
- Combine Ingredients in the Slow Cooker: In the slow cooker, whisk together the soy sauce, water, brown sugar, minced garlic, ground ginger, and red pepper flakes (if using).
- Add the Beef: Add the seared (or unseared) beef to the slow cooker, making sure it’s submerged in the sauce.
- Cook: Cover and cook on low for 4-6 hours, or on high for 2-3 hours. The beef is ready when it’s very tender. The longer it cooks on low, the more tender it will become. So if you have the time, I always opt for the longer, slower cook. You can do a quick check by seeing if the beef is easily shredded with a fork.
- Thicken the Sauce (Optional): If you want a thicker sauce, about 30 minutes before the end of the cooking time, take out about ½ cup of the sauce and whisk in 1 tablespoon of cornstarch until smooth. Pour this mixture back into the slow cooker and stir well.
- Serve: Once the beef is cooked and the sauce is to your liking, it’s time to serve! Garnish with sliced green onions and sesame seeds.
Variations & Tips for Slow-Cooker Mongolian Beef
- Spice it Up: If you like things a little hotter, add more red pepper flakes, or even a dash of sriracha to the sauce.
- Add Veggies: Feel free to toss in some vegetables during the last hour of cooking. Broccoli florets, sliced bell peppers, or snow peas work great.
- Make-Ahead: You can sear the beef and combine all the sauce ingredients in the slow cooker the night before. Then, just turn it on in the morning.
- Storage: Leftovers can be stored in an airtight container in the refrigerator for up to 3 days.
- Reheating: Reheat gently in the microwave or on the stovetop. You might need to add a splash of water if the sauce has thickened too much.
- Serving Suggestions: Serve over rice, noodles, or quinoa. It’s also delicious with a side of steamed vegetables.
Key Details
- Prep time: 15 minutes
- Cook time: 4-6 hours on low, 2-3 hours on high
- Total time: 4 hours 15 minutes (on low) to 6 hours 15 minutes (on low), or 2 hours 15 minutes (on high) to 3 hours 15 minutes (on high)
- Servings: 6
- Equipment you’ll need: Slow cooker, large skillet (optional), whisk, cutting board, knife
Slow-Cooker Mongolian Beef
Ingredients
- 1 ½ pounds flank steak thinly sliced against the grain
- ¼ cup cornstarch
- 2 tablespoons olive oil
- ½ cup soy sauce low sodium is best
- ½ cup water
- ¾ cup brown sugar packed
- 1 tablespoon minced garlic about 3 cloves
- 1 teaspoon ground ginger
- ¼ teaspoon red pepper flakes optional, for a little heat
- Green onions sliced (for garnish)
- Sesame seeds for garnish
Instructions
- Prepare the Beef: First, take your flank steak and slice it thinly against the grain. This helps make it extra tender. Then, put the sliced beef in a large zip-top bag or bowl and add the cornstarch. Toss it all together until the beef is evenly coated. This helps to thicken the sauce later.
- Sear the Beef (Optional but Recommended): Heat the olive oil in a large skillet over medium-high heat. Add the beef and sear it for about 2-3 minutes per side, just until it's browned. You don't need to cook it all the way through. This step adds extra flavor, but you can skip it if you're short on time.
- Combine Ingredients in the Slow Cooker: In the slow cooker, whisk together the soy sauce, water, brown sugar, minced garlic, ground ginger, and red pepper flakes (if using).
- Add the Beef: Add the seared (or unseared) beef to the slow cooker, making sure it's submerged in the sauce.
- Cook: Cover and cook on low for 4-6 hours, or on high for 2-3 hours. The beef is ready when it's very tender. The longer it cooks on low, the more tender it will become. So if you have the time, I always opt for the longer, slower cook. You can do a quick check by seeing if the beef is easily shredded with a fork.
- Thicken the Sauce (Optional): If you want a thicker sauce, about 30 minutes before the end of the cooking time, take out about ½ cup of the sauce and whisk in 1 tablespoon of cornstarch until smooth. Pour this mixture back into the slow cooker and stir well.
- Serve: Once the beef is cooked and the sauce is to your liking, it's time to serve! Garnish with sliced green onions and sesame seeds.