Slow Cooker Mongolian Beef is a comforting, sweet-and-savory dish made with tender beef cooked gently in a rich sauce. The slow cooker does all the work, making this an easy dinner for busy days. It’s perfect served over rice and tastes just like a takeout favorite made at home.

Why You’ll Love It

This recipe delivers deep flavor with very little effort. The beef turns soft and juicy, while the sauce balances sweetness and savory notes beautifully. Everything cooks in one pot, which means easy prep and easy cleanup.

Slow cooker Mongolian beef served in a blue bowl, featuring tender beef strips coated in a glossy dark sauce, garnished with fresh green onions.

What You’ll Need (Ingredients)

Flank steak (thinly sliced) – Becomes tender when slow cooked and absorbs the sauce well.
Soy sauce – Provides savory depth and saltiness.
Brown sugar – Adds sweetness and helps create a glossy sauce.
Garlic – Brings bold flavor to the dish.
Fresh ginger – Adds warmth and balance.
Water or low-sodium broth – Helps form the cooking sauce.
Cornstarch – Thickens the sauce at the end, if desired.
Green onions (optional) – For fresh garnish when serving.

Tools for This Recipe

Mixing bowls
Whisk
Spatula
Slow cooker
Knife
Cutting board
Measuring cups and spoons

How to Make It (Step-by-Step Overview)

Step Block 1 — Prep & Sauce

Slice the flank steak thinly against the grain.
In a mixing bowl, whisk together soy sauce, brown sugar, garlic, ginger, and water until smooth.

Step Block 2 — Cook & Thicken

Place the sliced beef into the slow cooker.
Pour the sauce over the beef and stir gently to coat.
Cover and cook on LOW for about 3 hours, until the beef is tender.
For a thicker sauce, stir in a cornstarch slurry and cook on HIGH for 15–30 minutes.

Helpful Tips

Always slice beef against the grain for the best texture.
Avoid overcooking on HIGH, as the beef may dry out.
Taste the sauce before serving and adjust sweetness if needed.

Substitutions & Variations

Beef alternatives: Sirloin or skirt steak work well.
Gluten-free option: Use gluten-free soy sauce.
Vegetable add-ins: Broccoli, bell peppers, or snap peas can be added during the last hour of cooking.
Spicy version: Add crushed red pepper flakes to the sauce.

What to Serve With It

Steamed white or jasmine rice
Brown rice for a heartier option
Stir-fried vegetables
Light cucumber salad
Hot tea or fruit-based drinks

Leftovers & Storage

Room temperature: Do not leave out longer than 2 hours.
Fridge: Store in an airtight container for up to 4 days.
Freezer: Freeze for up to 3 months.
Reheating: Warm gently on the stove or in the microwave.

FAQs

Can I prepare this ahead of time?
Yes, you can slice the beef and mix the sauce a day in advance.

Do I need to brown the beef first?
No, the slow cooker handles everything without pre-browning.

Can I double the recipe?
Yes, as long as your slow cooker is large enough.

How do I know when it’s done?
The beef should be very tender and easy to pull apart.

Is the sauce very sweet?
It’s balanced, but you can reduce the sugar slightly if preferred.

Conclusion

Slow Cooker Mongolian Beef is an easy, comforting meal that delivers big flavor with minimal effort. It’s perfect for family dinners or meal prep and tastes just as good the next day. Once you try it, it’s sure to become a regular on your dinner rotation.

Full Recipe