Creating Hoisin Beef Noodles is simple if you follow these easy steps:

1. Cook Noodles: Begin by cooking the noodles according to package instructions. Drain and set aside.
2. Prep Beef: Slice the beef sirloin thinly against the grain for tenderness.
3. Heat Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.
4. Cook Beef: Add the sliced beef to the hot skillet. Stir-fry for 3-5 minutes or until browned. Remove beef and set aside.
5. Stir-Fry Vegetables: In the same skillet, add garlic, onion, and bell pepper. Stir-fry for 2-3 minutes until the vegetables are tender.
6. Add Greens: Toss in the spinach or bok choy and cook until wilted, about 1-2 minutes.
7. Combine Ingredients: Return the cooked beef to the skillet. Add the cooked noodles.
8. Add Sauces: Pour in the hoisin sauce, soy sauce, rice vinegar, and sesame oil. Toss everything together until evenly coated. Season with salt and pepper to taste.
9. Heat Through: Cook for another 2-3 minutes until everything is heated through.
10. Serve: Garnish with chopped green onions and sesame seeds, if desired.

Following these steps will lead to a delightful and fulfilling meal that everyone will rave about!