Follow these simple steps to create your delicious Mongolian Beef Noodles:

1. Cook Noodles: Begin by cooking the egg noodles according to package instructions. Drain and set aside.
2. Prepare Beef: Season the sliced flank steak with salt and pepper.
3. Heat Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.
4. Stir-Fry Beef: Add the beef to the hot skillet and stir-fry until browned, about 3-4 minutes. Remove the beef and set aside.
5. Sauté Aromatics: In the same skillet, add garlic and ginger. Sauté for about 30 seconds until fragrant.
6. Add Vegetables: Toss in the broccoli and bell peppers. Stir-fry for about 3 minutes until the vegetables are tender-crisp.
7. Combine Ingredients: Return the beef to the skillet. Add the soy sauce, brown sugar, and red pepper flakes (if using). Mix well.
8. Add Noodles: Incorporate the cooked egg noodles into the skillet, tossing to coat everything evenly with the sauce.
9. Final Touch: Stir in the chopped green onions and cook for an additional minute.
10. Serve: Remove from heat and transfer the Mongolian Beef Noodles to serving plates. Garnish with extra green onions if desired.

By following these steps, you’ll have a delicious dish ready to enjoy in no time!