When we say this is the best Mongolian beef, we mean it.
- In a medium bowl, whisk together brown sugar, soy sauce, garlic, ginger, 2 teaspoons vegetable oil, and water.
- In another bowl, combine flank steak and cornstarch. Mix until the steak is fully coated.
- Heat soy sauce mixture in a saucepan until slightly thickened, about 5 to 10 minutes. Remove from heat.
- Add 1/2 cup vegetable oil to a large skillet. Add steak and fry until steak is browned and cooked through. Remove steak from skillet and drain on a paper towel-lined plate.
- Add steak and soy sauce to a saucepan over medium heat. Cook until sauce is thick, about 3 minutes.
- Remove from heat, serve over rice or noodles, garnish with sliced green onions and enjoy!