- Marinate the lamb: Pat-dry the lamb tenderloin fillets. Trim off excess fat and remove any sinew. Thinly slice into strips and add to a medium bowl, followed by the low sodium light soy sauce, dark soy sauce, Shao Xing rice wine, ground white pepper, potato starch and sesame oil. Mix well to combine and set aside for 20 minutes while you prepare the rest of the ingredients.
- Make the sauce: Whisk together the low sodium light soy sauce, Shao Xing rice wine, Chinkiang vinegar, hoisin sauce, dark soy sauce, sesame oil, pure chili oil (if using), white sugar, kosher salt, ground cinnamon, ground cumin, crushed red pepper flakes and water in a small measuring cup (for easier pouring) or bowl.
- Prepare the fresh and dry ingredients: Chop/slice the Welsh onion, garlic, ginger, fresh red chilies, and dried red chilies as indicated in the ‘ingredients’ section. (Pro-tip: Deseed the fresh red chilies and shake out and discard some or all of the seeds from the dried red chilies for a milder dish.)
For the Mongolian Lamb Stir-fry:
- Cook the lamb: Heat 3 tablespoons of canola oil in a large wok over high heat. Once hot, add the marinated lamb and immediately spread out the pieces in the wok. Cook undisturbed for 30 seconds, then stir-fry for 1 minute or until golden brown and cooked through. Using a slotted spoon, transfer to a fine mesh strainer held above the wok, allowing the excess oil to drip back in. Then tip the lamb into to a clean bowl. Spoon out and discard any gluggy bits from the wok.
- Sauté the aromatics: Heat the oil in the wok over medium-high heat. Once hot, add the garlic and ginger and stir-fry for 30 seconds until fragrant. Add the fresh and dried red chilies and stir-fry for another 20-30 seconds.
- Add the shredded Welsh onion. Add the Welsh onion and stir-fry for 30 seconds to combine.
- Add the lamb and sauce. Add the lamb and all the juices in the bowl back into the wok and pour the sauce over everything. Stir-fry for 1 minute or so, until the sauce thickens and coats everything well. Switch off the heat.
- To Serve: Transfer to a serving plate/dish. Sprinkle with toasted white sesame seeds and chopped spring onion and serve immediately with warm steamed rice.