Name: Slow Cooker Mongolian Beef
Prep time: 15 min
Cook time: 255 min
Total time: 270 min
Ingredients: 1 1/2 pounds beef flank steak or sirloin (sliced thin against the grain); 1/2 cup soy sauce (low-sodium); 3/4 cup brown sugar (packed); 6 cloves garlic (minced); 1 tablespoon fresh ginger (minced); 1/2 cup beef broth; 3 tablespoons cornstarch; 3 tablespoons cold water; 3 green onions (thinly sliced, for garnish); 1 tablespoon vegetable oil

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Slow Cooker Mongolian Beef is tender strips of beef simmered low and slow in a sticky, garlicky soy sauce until the edges turn glossy and dark. It's one of those dinners that tastes like takeout but costs a fraction and barely dirties a dish.

You only need beef, brown sugar, soy sauce, garlic, and about 15 minutes of prep before the crockpot does the rest over 4 hours. Save it for later for busy weeknights or Sunday meal prep.

Prep	Cook	Total	Servings	Difficulty
15 min	4 h 15 min	4 h 30 min	4 servings	Advanced

Quick Facts

Slow Cooker Mongolian Beef with Sticky Garlic Sauce

Why You'll Love This Recipe

Hands-off cooking. Once it's in the crockpot, you walk away for hours.
Pantry ingredients. Soy sauce, brown sugar, and garlic are things most of us already have.
Kid-friendly flavor. The sauce is sweet and savory, not spicy, unless you want it to be.
Make-ahead friendly. It tastes even better the next day after the sauce soaks in.
Budget stretcher. A cheaper cut of beef turns tender here, no steak prices required.

Slow Cooker Mongolian Beef Ingredients

Ingredients for Slow Cooker Mongolian Beef with Sticky Garlic Sauce

Beef flank steak or sirloin – sliced thin against the grain, this is what turns soft after hours in the sauce. Chuck roast works too if you have more time.
Soy sauce – the salty backbone of the sauce. Low-sodium keeps things from tasting too sharp.
Brown sugar – gives the sauce its sticky, almost caramelized finish.
Garlic – lots of it, minced fresh for real flavor instead of jarred paste.
Fresh ginger – adds warmth and a little bite that balances the sweetness.
Beef broth – thins the sauce just enough so it coats the beef without drowning it.
Cornstarch – whisked into the sauce near the end to thicken it into that glossy coating.
Green onions – sliced thin for garnish, adding color and a sharp bite at the end.

Skip the Worcestershire sauce some recipes call for, since it often contains anchovies and malt vinegar; a splash of soy sauce with a little rice vinegar does the same job. You'll find exact amounts in the recipe card below.

Ways to Change It Up

Swap the protein. Ground beef works in a pinch, similar to the method in our Mongolian Ground Beef recipe.
Add vegetables. Broccoli, snap peas, or bell peppers stirred in during the last 30 minutes add color and crunch.
Turn up the heat. A few shakes of red pepper flakes or a spoon of chili garlic sauce brings real warmth.
Go noodle-style. Toss the finished beef with noodles like we do in our Mongolian Beef Noodles recipe.
Try the stovetop. No crockpot? A Dutch oven on low heat for about an hour gets you there too.

How to Make Slow Cooker Mongolian Beef

Slice the beef. Cut it thin, against the grain, so it stays tender instead of chewy after hours of cooking.
Build the sauce. Whisk together soy sauce, brown sugar, garlic, ginger, and broth right in the crockpot insert.
Add the beef and cook. Stir the beef into the sauce, cover, and cook on low for about 4 hours, until it's soft and pulls apart easily with a fork.
Thicken the sauce. Whisk cornstarch with a little cold water, stir it in, and cook uncovered on high for 10-15 minutes until the sauce turns glossy and clings to a spoon.
Garnish and serve. Scatter sliced green onions over the top right before serving, while the sauce is still hot and shiny.

Pro Tips from Our Kitchen

Slice against the grain. This single step matters more than anything else for texture, so look for the direction of the muscle fibers and cut across them.
Don't skip the thickening step. Without the cornstarch slurry, the sauce stays thin and watery instead of sticky.
Taste before serving. Brown sugar brands vary, so adjust with a splash more soy sauce if it's too sweet.
Use low heat for tougher cuts. Chuck needs the full low setting and extra time to soften properly.
Don't lift the lid. Every peek lets out heat and adds cooking time.

What to Serve With It

Steamed white rice is the classic base, soaking up every bit of that sticky sauce. Stir-fried broccoli or snap peas add crunch and color on the side. For a heartier spread, our Crock Pot Cheesy Scalloped Potatoes make an unexpected but comforting pairing, and Slow Cooker Cheddar Corn Recipe brings a sweet, creamy contrast to the salty beef.

Storage and Reheating

Store leftovers in an airtight container in the fridge for up to 4 days. The sauce actually deepens in flavor overnight. For longer storage, freeze in a sealed container for up to 3 months and thaw overnight in the fridge before reheating. Warm it gently on the stovetop over medium-low heat, or in the microwave in 30-second bursts, stirring between each, until it's heated through.

Slow Cooker Mongolian Beef FAQ

Can I use chicken instead of beef?

Yes, boneless chicken thighs work well in the same sauce, though cooking time drops to about 3 hours on low since chicken cooks faster than beef.

Can I double the recipe?

Yes, just make sure your crockpot has enough room for the beef to sit in a single layer or two, and add about 30 extra minutes to the cooking time.

Do I need a crockpot for this?

A crockpot is easiest for hands-off cooking, but a covered Dutch oven on the stovetop over low heat works too, checking every 20 minutes so it doesn't dry out.