This 5-ingredient slow cooker Mongolian beef is my go-to when I need something that feels a little special but I absolutely do not have time to stand over a hot stove. It leans on the classic takeout-style Mongolian beef flavors—soy, brown sugar, garlic, and ginger—then lets the slow cooker do all the work. Using thin-sliced raw flank steak means it turns out incredibly tender and soaks up a glossy, dark amber sauce while you’re off doing a million other things, making it perfect for feeding a hungry crowd on a busy weeknight or casual get-together.
Serve this Mongolian beef piled over hot steamed rice or jasmine rice so it can soak up all that glossy, savory-sweet sauce. I like to add a simple side of roasted or steamed veggies—broccoli, green beans, or snap peas are all great—to round things out without much effort. If you’re feeding a crowd, set it up buffet-style in the slow cooker on “warm” with a big spoon, a pot of rice, and maybe a simple green salad or store-bought egg rolls so everyone can help themselves and you’re not stuck in the kitchen.
5-Ingredient Slow Cooker Mongolian BeefServings: 6-8
Ingredients
2 1/2 pounds flank steak, very thinly sliced against the grain
1 cup low-sodium soy sauce
1 cup packed brown sugar (light or dark)
6 cloves garlic, minced (about 2 tablespoons)
2 teaspoons ground ginger (or 1 tablespoon grated fresh ginger)
Directions
Trim any excess fat from the flank steak, then slice it very thinly against the grain into bite-size strips. The thinner the slices, the more tender they’ll be after slow cooking.
In a medium bowl or large measuring cup, whisk together the low-sodium soy sauce, brown sugar, minced garlic, and ground ginger until the sugar is mostly dissolved and everything is well combined.
Place the thin-sliced raw flank steak into the slow cooker, spreading it out as evenly as you can so the pieces aren’t all clumped together.
Pour the soy-garlic-ginger mixture evenly over the steak, using a spoon or tongs to gently toss and coat all the slices in the sauce.
Cover the slow cooker with the lid and cook on LOW for 4–5 hours, or on HIGH for 2–3 hours, until the beef is very tender and the sauce has turned into a dark amber, glossy glaze. Give it a gentle stir once or twice during cooking if you’re home, to make sure all the pieces stay coated.
Once the beef is tender and the sauce has thickened slightly, taste and adjust seasoning if needed (you can add a splash more soy for saltiness or a pinch more brown sugar for sweetness). If the sauce is thinner than you like, remove the lid and cook on HIGH for an additional 15–20 minutes to let it reduce and concentrate.
Switch the slow cooker to WARM for serving. Give everything a final stir so the tender chunks of beef are fully coated in the glossy sauce, then serve hot straight from the slow cooker over rice or your favorite sides.
Variations & Tips
If you want a little heat, stir in 1–2 teaspoons of crushed red pepper flakes or a squirt of sriracha with the soy sauce mixture before pouring it over the beef. For a slightly lighter version, you can use 3/4 cup brown sugar instead of a full cup and add a splash of water if you prefer the sauce less intense. To bulk it up for a bigger crowd without adding more meat, you can toss in a bag of frozen stir-fry vegetables during the last 30–45 minutes of cooking; just note that this technically adds more ingredients beyond the base five. If you like a thicker, almost sticky sauce, whisk 1 tablespoon cornstarch with 2 tablespoons water and stir it into the slow cooker during the last 20–30 minutes on HIGH until the sauce turns extra glossy and clings to the beef. For food safety, always start with fresh, fully thawed flank steak—never cook from frozen in the slow cooker, as it can sit too long at unsafe temperatures. Make sure your slow cooker reaches and maintains a safe temperature (use the LOW or HIGH settings, not “warm” for cooking). Leftovers should be cooled and refrigerated within 2 hours and eaten within 3–4 days, or frozen for up to 2–3 months in an airtight container. Reheat leftovers until steaming hot before serving.
