Instructions

1. In a medium bowl, combine the soy sauce, brown sugar, and cornstarch. Stir until well mixed.
2. Add the thinly sliced flank steak to the marinade and let it sit for at least 10 minutes to soak up the flavors.
3. In a large skillet or wok, heat the vegetable oil over medium-high heat. Once hot, add the marinated beef in a single layer and cook for 2-3 minutes until browned, stirring occasionally.
4. Add the minced ginger and garlic to the skillet, stirring for about 30 seconds until fragrant.
5. Add the chopped green onions to the skillet and stir-fry for an additional 1-2 minutes, until the green onions are tender.
6. Drizzle the sesame oil over the stir-fry and mix well to combine.
7. Serve the Mongolian beef over a bed of cooked jasmine rice.