
Marinate the beef. Combine all of the marinated beef ingredients in a medium mixing bowl and toss until the beef is evenly coated. Let the mixture for at least 10 minutes.
Prepare the stir-fry sauce. Meanwhile, whisk together the stir-fry sauce ingredients in a small mixing bowl until combined.
Prepare the noodles. Cook the rice noodles according to package instructions, then drain until ready to use.
Stir-fry the beef. Heat 2 tablespoons oil in a large sauté pan or wok over medium-high heat. Add the marinated beef in a single layer (you may need to do this in two batches, depending on the size of the pan) and cook undisturbed for 1-2 minutes per side until the beef seared and tender. Transfer the beef to a clean plate and set aside.
Stir-fry the veggies. Add the remaining 1 tablespoon oil to the pan. Add the onion and sauté, stirring occasionally, for 3 minutes. Add the garlic and ginger and sauté, stirring frequently, for 1 minute.
Combine. Add the green onions, bean sprouts, cooked noodles and cooked beef. Toss until the ingredients are evenly combined. Remove pan from heat. Taste and season with additional soy sauce, if needed.
Serve. Serve warm and enjoy!