Easy Mongolian Beef: A 25-Minute Skillet Dinner for Families

This easy Mongolian beef is a weeknight skillet dinner made with thinly sliced flank steak, a cornstarch coating and a four-ingredient soy-brown sugar sauce, ready in about 25 to 30 minutes. Serve it over rice or noodles with a green vegetable. The dish is a Chinese American takeout favorite rather than a traditional Mongolian one, and it is easy to make milder for children. Below you will find the recipe, timing notes, a kid-friendly version and side dish options.

Ingredients (serves 4)

Beef

• 1 1/2 pounds flank steak
• 1/4 cup cornstarch
• 3 tablespoons neutral oil, such as canola or vegetable, divided

Sauce

• 3 cloves garlic, minced
• 1 tablespoon fresh ginger, grated (or 1/2 teaspoon ground ginger)
• 1/2 cup low-sodium soy sauce
• 1/2 cup water
• 1/3 cup packed brown sugar
• 1 teaspoon rice vinegar (optional)
• 1/4 teaspoon red pepper flakes (optional, for adults)

To finish

• 4 green onions, cut into 2-inch pieces
• 1 teaspoon toasted sesame oil (optional)
• Cooked rice or noodles, for serving

Timing at a glance

Start the rice or noodles when you put the steak in the freezer so everything finishes together.

Instructions

1. Chill the steak. Put the flank steak in the freezer for 15 to 20 minutes. A firm steak is much easier to slice thinly.
2. Slice against the grain. Flank steak has visible lines running in one direction. Cut across those lines into slices about 1/4 inch thick. Cutting against the grain keeps the meat tender.
3. Coat the beef. Toss the slices with the cornstarch in a bowl or large zip-top bag until lightly coated. Shake off any excess.
4. Mix the sauce. In a bowl, whisk together the soy sauce, water, brown sugar and rice vinegar. Set it next to the stove.
5. Brown the beef. Heat 2 tablespoons of oil in a large skillet over medium-high heat. Add half the beef in a single layer and cook for about 1 to 2 minutes per side until browned. Move it to a plate. Add the second batch. Do not crowd the pan or the beef will steam instead of sear.
6. Cook the aromatics. Lower the heat to medium. Add the remaining tablespoon of oil, the garlic, the ginger and the red pepper flakes if using. Stir for 30 seconds until fragrant.
7. Make the sauce. Pour in the sauce. It will bubble and thicken in about 2 to 3 minutes as the cornstarch left in the pan cooks.
8. Combine. Return the beef to the skillet, add the green onions and toss for 1 to 2 minutes until everything is hot and coated. Stir in the sesame oil if using, and serve at once.

How to tell it is done

Thin strips cook very fast. Cook until no pink remains and the sauce is bubbling. If you want to check with a thermometer, test the thickest piece. The U.S. Department of Agriculture lists 145°F (62.8°C) with a 3-minute rest as the safe minimum internal temperature for beef steaks, and 160°F for ground beef. See the USDA’s safe temperature chart. Very thin strips are hard to probe, so when in doubt, cut a piece open and cook it a little longer.

Kid-friendly version

• Make the sauce milder. Skip the red pepper flakes and ginger, or use half the ginger. Reduce the soy sauce to 1/3 cup and increase the water to 2/3 cup.
• Serve the sauce on the side for children who like their food plain.
• Cut small. For young children, cut the beef into small pieces. Talk with your pediatrician about when your child is ready for firmer meats.
• Add a familiar side. Plain rice, noodles and a vegetable your child likes make the plate less intimidating.

Jobs for children

• Shake the beef and cornstarch in the bag.
• Whisk the sauce, with an adult measuring the soy sauce.
• Snip the green onions with kitchen scissors, with supervision.
• Set the table and fill glasses.

Adults should handle the knife, the hot oil and the stove.

Side dishes

Swaps and tips

• Other cuts. Sirloin or skirt steak works if sliced thin against the grain.
• Chicken or tofu. Slice boneless chicken thighs thin and cook to 165°F. For tofu, press and cube extra-firm tofu.
• Soy, wheat or gluten. Soy sauce contains soy and usually wheat. Tamari may work for a wheat-free diet, but check the label. Ask your pediatrician or an allergist about food allergies.
• Less sodium. Use low-sodium soy sauce, as in the recipe, and skip adding salt.
• Stretch the meal. Add sliced bell peppers or broccoli florets to make the beef go further. For a week of low-cost dinners, see our family meal plan on a budget.
• Make ahead. Slice and coat the beef in the morning and mix the sauce the night before. Keep both in the refrigerator.

Looking for another one-pan weeknight dinner? Try our skillet chicken pasta.

Storing leftovers

Refrigerate leftovers within 2 hours of cooking, or within 1 hour if the room is hotter than 90°F. This applies to cooked rice too. Use refrigerated leftovers within 3 to 4 days and reheat to 165°F. Freeze in an airtight container for longer storage, and use within a couple of months for the best quality.

Bottom line

Slice flank steak thin against the grain, coat it in cornstarch, sear it in batches and finish it in a quick soy-brown sugar sauce. The whole dinner takes about half an hour, and it adapts easily for children by toning down the sauce and cutting the beef small.

FAQ

Why is my beef tough?

Usually it was sliced with the grain, sliced too thick or overcooked. Slice thin against the grain and cook only until browned.

Can I use a different cut of steak?

Yes. Sirloin and skirt steak work if sliced thin against the grain. Tougher cuts like chuck are better for slow cooking.

Can I make it ahead?

You can prep the beef and the sauce ahead and cook just before dinner. Cooked Mongolian beef also reheats well, though the coating softens.

How do I make the sauce thicker?

Simmer it a little longer. If it is still thin, stir 1 teaspoon of cornstarch into 1 tablespoon of cold water and add it to the pan, then cook for another minute.