Mongolian beef is a Chinese-American takeout-style dish of thin beef strips coated in a glossy, sweet-savory sauce, usually served over rice. This gluten-free version uses tamari instead of regular soy sauce, with ginger, garlic, and a quick cornstarch-thickened sauce for familiar flavor without a long marinade.
Ingredients
- 1¼ lb flank steak (570 g), trimmed of excess fat
- 3 tbsp cornstarch (24 g), for coating the beef
- 2 tbsp neutral high-heat oil (30 ml), such as avocado, canola, or sunflower oil, divided
- ⅓ cup gluten-free tamari (80 ml), plus more only if needed at the table
- ⅓ cup packed light brown sugar (about 67 g)
- ⅓ cup water (80 ml), for the sauce
- 1 tbsp unseasoned rice vinegar (15 ml)
- 1 tsp toasted sesame oil (5 ml)
- 3 garlic cloves (about 9 g), finely minced
- 1 tbsp finely grated fresh ginger (about 6 g)
- 2 tsp cornstarch (about 5 g), for thickening the sauce
- 1 tbsp cold water (15 ml), to mix with the sauce cornstarch
- 4 scallions (about 60 g), thinly sliced, with white and green parts separated
- ¼ tsp red pepper flakes (about 0.5 g), optional
- ¼ tsp ground black pepper (about 0.5 g)
Check that the tamari and cornstarch are labeled gluten-free, especially if cooking for someone who must avoid gluten. Tamari is often made without wheat, but not every brand or product is guaranteed gluten-free. If you cannot find gluten-free tamari, use a certified gluten-free soy sauce; it may taste a little lighter or less rounded. Do not substitute ordinary soy sauce, which commonly contains wheat. The rice vinegar should be plain and unseasoned, since seasoned varieties may include extra sugar or other ingredients.
Instructions
- Slice the steak. Pat the flank steak dry with paper towels so it browns rather than steams. Look for the direction of the long muscle fibers, then slice across them into thin strips about ¼ inch (6 mm) thick. Cutting across the grain shortens the fibers and makes each bite easier to chew. If the steak is unusually wide, cut it into manageable sections before slicing.
- Mix the sauce and coating. In a small bowl, stir together the tamari, brown sugar, water, rice vinegar, and sesame oil until the sugar is mostly dissolved. In a separate small cup, combine the 2 teaspoons of cornstarch with 1 tablespoon of cold water; stir again just before using, because the starch settles. Toss the sliced beef with the 3 tablespoons of cornstarch and black pepper until the pieces have a light, even coating. Shake off any thick clumps.
- Heat the pan. Set a large skillet or wok over medium-high heat and let it get hot before adding 1 tablespoon of the neutral oil. A wide pan gives the beef room to brown. If your skillet is small, plan to cook the steak in three batches rather than crowding the surface; crowded meat releases moisture and turns pale before it can sear.
- Sear the beef in batches. Arrange a single layer of beef in the hot pan. Cook for about 1 to 2 minutes on the first side, then turn the strips and cook for another 1 to 2 minutes, just until browned and nearly cooked through. Transfer them to a clean plate and repeat with the remaining oil and beef. The precise time depends on strip thickness and pan heat, so use temperature rather than color alone to judge doneness.
- Check doneness and rest. Check the thickest pieces with a food thermometer. The USDA FSIS safe minimum for whole cuts of beef is 145°F (63°C), followed by a 3-minute rest. Move the cooked strips to a clean plate and let them rest for that full 3 minutes while you make the sauce. Thin strips can be awkward to probe; stack a few pieces together to get a reliable reading without touching the pan.
- Cook the aromatics and sauce. Carefully lower the heat to medium. Add the white parts of the scallions, garlic, ginger, and red pepper flakes, if using. Stir for about 30 seconds, just until fragrant; garlic can turn bitter if it browns. Pour in the tamari mixture and bring it to a gentle simmer, stirring to dissolve any browned bits from the pan. Stir the cornstarch slurry once more, then pour it in while stirring. Simmer for about 1 minute, until the sauce looks glossy and lightly thickened.
- Coat the beef and serve. Return the rested beef and any juices on the plate to the skillet. Toss for 1 to 2 minutes, just until the strips are hot and evenly coated; avoid a long boil, which can make thin beef tough. Fold in most of the green scallion tops, taste the sauce, and serve straight away with the remaining scallions scattered over the top.
Tips
- Cut evenly and across the grain. Similar-size strips cook at roughly the same rate, while slicing across the muscle fibers helps keep the beef tender. If the grain is hard to see, check the direction of the visible lines on the raw steak before cutting it into sections.
- Use batches instead of extra heat. A crowded pan makes the beef steam, and turning the burner higher does not fix the lack of space. Let the skillet reheat briefly between batches. If the coating leaves browned bits, that is useful flavor for the sauce; if it begins to scorch, wipe out the burnt residue before adding the aromatics.
- Keep the sauce balanced. Tamari brands vary in saltiness, so taste the finished sauce before adding anything extra. If it is too salty, stir in a tablespoon of water; if it tastes too sweet, add a small splash of rice vinegar. Add either gradually so the sauce stays thick enough to cling to the beef.
- Make the gluten-free check part of prep. Verify the tamari, vinegar, cornstarch, and any packaged sides on their labels. If you are preparing food for someone with celiac disease or a serious gluten sensitivity, use clean utensils and a clean pan, and keep the meal away from crumbs or shared cooking surfaces.
Serving Suggestions
Serve the beef over steamed white rice, brown rice, or jasmine rice so the grains can catch the extra sauce. Rice is not included in the ingredient quantities because it can be cooked separately to suit your table; for four people, about 1½ cups (285 g) of uncooked rice typically makes a generous amount, though varieties absorb different amounts of water. For a vegetable-forward plate, add steamed broccoli, sautéed snap peas, or bok choy. Keep vegetables on the side if you want the beef to stay crisp around the edges, or add them to the skillet at the end if you prefer everything coated in sauce.
For a fuller dinner, pair the beef and rice with a simple cucumber salad or lightly dressed shredded cabbage to bring a cool, crisp contrast to the sweet-savory sauce. A sprinkle of sesame seeds is a fitting garnish if they are safe for everyone eating. Put extra tamari, chili flakes, or sliced scallion on the table rather than adding a lot to the pan; diners can adjust their own portions without changing the balance of the whole batch.
Variations
Adjust the heat: The recipe is gently spicy only if you include the pepper flakes. Leave them out for a mild version, or add more at the table for people who want stronger heat. A small amount of finely sliced fresh chili can also be added with the garlic and ginger, but it will bring a brighter, more direct heat than dried flakes.
Use another quick-cooking cut: Sirloin or flat iron steak can stand in for flank steak. Slice it across the grain and keep the strips thin; the exact cooking time may change depending on the cut and thickness. Avoid very lean cuts cooked for too long, because the final toss in sauce is brief and the strips can become dry if they are left in the pan.
Make it less sweet: Reduce the brown sugar to ¼ cup (about 50 g) for a less-sweet sauce. It will still thicken, but the sauce will taste more savory and the tamari may come forward more strongly. Do not remove all the sugar without adjusting the liquid and thickener, since the sauce may taste sharply salty and have a different consistency.
Add vegetables: Stir-fry broccoli florets, bell pepper strips, or sliced mushrooms separately, then return them to the pan with the beef. Cook vegetables until just tender before adding the sauce so they do not release too much water into it. If you add a large amount, make extra sauce by scaling up the tamari, water, and thickener together rather than pouring in tamari alone.
Storage and Reheating
Refrigerate leftover beef within 2 hours of cooking, in a shallow airtight container. It keeps for 3 to 4 days in the refrigerator. Store rice separately when possible, since it reheats more evenly that way and is easier to portion. For longer storage, freeze the beef in a freezer-safe container for up to 2 months for best quality. Thaw it overnight in the refrigerator before reheating; the sauce may separate slightly after freezing, but stirring as it warms usually brings it back together.
Reheat a portion in a skillet over medium-low heat with a tablespoon or two of water to loosen the sauce, stirring gently until hot throughout. You can also use a microwave-safe dish, covered loosely, in short intervals, stirring between each interval. Reheat leftovers to 165°F (74°C), checked with a food thermometer. Avoid repeated heating and cooling, which can dry out the beef; warm only the amount you plan to eat.
Frequently Asked Questions
Is Mongolian beef actually from Mongolia?
The restaurant-style dish commonly called Mongolian beef is associated with Chinese-American cooking, and its name does not mean it is a traditional Mongolian dish. Versions differ between restaurants and home cooks, especially in sweetness, heat, and the vegetables included. This recipe follows the familiar style of thin beef in a glossy, sweet-savory sauce while using gluten-free tamari.
Can I use regular soy sauce instead of tamari?
Regular soy sauce is not a suitable swap for a gluten-free meal unless its label specifically certifies it as gluten-free; many soy sauces contain wheat. Use gluten-free tamari or certified gluten-free soy sauce instead. The flavor will vary a little by brand, so taste the sauce before serving rather than automatically adding more salt or tamari.
Can I prepare the beef ahead of time?
You can slice the steak and prepare the sauce several hours ahead, keeping them covered separately in the refrigerator. For the best browning, wait to coat the beef with cornstarch until just before it goes into the hot pan; an early coating can become damp and sticky. Cooked beef can also be refrigerated and reheated, though it will be softer than freshly seared beef.
Why did my sauce turn lumpy or too thick?
Cornstarch can clump if it is added dry to hot liquid, so mix it with cold water first and stir the slurry again just before pouring it into the pan. If the sauce thickens more than you like, add water a tablespoon at a time while stirring over low heat. If it stays thin, simmer it briefly; if needed, mix a little more cornstarch with cold water before adding it rather than sprinkling starch directly into the skillet.
Can I make this without cornstarch?
For a cornstarch-free version, use arrowroot starch in the same amount for coating and start with about 1½ teaspoons (4 g) arrowroot mixed with cold water for the sauce. Arrowroot can make a glossy sauce, but it may turn slightly slippery if boiled hard, so add it near the end and keep the sauce at a gentle simmer. Check the package label to confirm it is gluten-free.
Related
- Slow Cooker Mongolian Beef with Kimchi
- Mongolian Steak Recipe with a Glossy Ginger-Garlic Sauce
- Mongolian Noodles Recipe with Quick Sweet-Savory Beef
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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