My husband asked for Mongolian beef recently, so I experimented until I had a Whole30-friendly version we both love. This sauce-forward, savory, and satisfying Whole30 Mongolian Beef Stir Fry delivers rich umami and a touch of heat while staying compliant. I serve it with quickly seared baby bok choy for color and nutrients, and cauliflower rice keeps the meal low-carb and Whole30-approved.
This recipe captures everything you love about the classic takeout dish—tender, thinly sliced beef coated in a glossy, savory sauce—without the refined sugars or non-compliant ingredients. The sauce is built from coconut aminos, rice vinegar, beef broth, and a hint of fish sauce for depth. Thin strips of flank or skirt steak get a light coating of arrowroot for a crisp exterior, then finish in the sauce with green onions. Quick-seared baby bok choy tossed with a splash of fish sauce adds a bright, savory counterpoint. Make it a weeknight staple: it cooks in about 30 minutes and serves four.
Ingredients
- 1½ pounds skirt or flank steak
- 1 teaspoon kosher salt
- ½ teaspoon freshly ground black pepper
- 1 tablespoon arrowroot starch
- 4 tablespoons avocado oil (divided)
- 3 garlic cloves, thinly sliced
- 1 (1-inch) piece fresh ginger, finely grated
- 1 teaspoon toasted sesame oil
- ½ teaspoon crushed red pepper flakes (optional)
- ½ cup low-sodium beef broth
- 6 green onions, sliced into 1½-inch pieces (white and green parts)
- ½ cup coconut aminos
- 1 tablespoon rice vinegar
- 1 teaspoon fish sauce (or lime juice if allergic)
- 1 tablespoon toasted sesame seeds, for serving
- 2 heads baby bok choy, rinsed, dried, and halved lengthwise
- Cauliflower rice, for serving (optional, to keep it Whole30)
Step-by-step
Step one: Prep the beef
Place the flank or skirt steak on a cutting board and cover with parchment or plastic wrap. Pound with a meat mallet or the back of a skillet until about ½ inch thick. Slice the steak against the grain into ¼-inch-thin strips. Put the slices in a large bowl and toss with the arrowroot starch, salt, and pepper until evenly coated.
Step two: Sear the steak
Heat 2 tablespoons of avocado oil in a large nonstick or heavy skillet over medium-high heat. Working in batches so you don’t overcrowd the pan, arrange the steak in a single layer and cook without moving it until a deep brown crust forms, about 3–4 minutes. Flip and cook another 3–4 minutes. Transfer cooked steak to a plate and repeat with remaining steak, adding more oil if needed.
Step three: Add aromatics and simmer
Return the skillet to medium-high heat and add the remaining oil if the pan is dry. Add the sliced garlic, grated ginger, toasted sesame oil, and crushed red pepper flakes; cook, stirring, for about 1 minute until fragrant. Pour in the beef broth and bring to a simmer, scraping up any browned bits from the pan. Let the broth reduce briefly, about 2–3 minutes.
Step four: Build the sauce and finish the beef
Return the seared beef to the skillet. Stir in the green onions, coconut aminos, rice vinegar, and fish sauce. Bring the mixture to a gentle simmer and cook, stirring often, until the sauce thickens and coats the beef, about 3–5 minutes. Remove from heat and keep warm.
Step five: Sear the baby bok choy
Heat 1 tablespoon avocado oil in a separate large skillet over medium-high heat. Place the halved bok choy cut-side down and sear until golden brown, 3–4 minutes per side. Add 1 teaspoon fish sauce (or a squeeze of lime if avoiding fish sauce) and toss to combine. Season with freshly ground black pepper to taste.
Step six: Serve and garnish
Divide cauliflower rice among bowls if using, then top with the Mongolian beef and seared baby bok choy. Sprinkle with toasted sesame seeds and extra sliced green onions if desired. Serve immediately.
Recipe FAQs
Is there a good substitute for arrowroot?
Yes—if you’re not following Whole30, cornstarch will work as a thickener and produce a similar crisp finish.
I’m allergic to fish sauce. What can I use instead?
Use fresh lime juice for brightness and acidity; it pairs well with the coconut aminos and still adds depth without fish-based ingredients.
Notes & Nutrition
Cook time: Approximately 30 minutes. Servings: 4.
Nutrition per serving (approximate): Calories: 460 kcal; Carbohydrates: 11 g; Protein: 38 g; Fat: 28 g; Saturated Fat: 6 g; Sodium: 1648 mg. Nutrition information is an estimate and should be used as a guideline only.
This Whole30 Mongolian Beef Stir Fry is quick to make, full of umami, and a great way to bring a favorite takeout flavor into a clean-eating plan. If you try it, snap a photo and share it with friends or family—it’s one of those meals people ask for again and again.