Begin by boiling water in a large pot. Add the egg noodles and cook according to the package instructions until al dente. Once cooked, drain and set aside.
In a large skillet or wok, heat the vegetable oil over medium-high heat.
Add the chopped onion and minced garlic to the skillet. Sauté for about 2-3 minutes until the onion is translucent.
Next, add the ground beef to the skillet. Cook until browned, breaking it apart with a spoon or spatula, which should take around 5-7 minutes.
Once the beef is browned, add the sliced bell pepper and snap peas (or green beans), cooking for an additional 3-4 minutes until the vegetables are slightly tender.
In a small bowl, mix together the soy sauce, oyster sauce, hoisin sauce, ground ginger, salt, and pepper. Pour this sauce over the beef and vegetables, stirring to combine. Let it cook for another 2 minutes, allowing the flavors to meld.
Add the cooked noodles to the skillet, tossing everything together to ensure the noodles are well-coated with the sauce and ingredients. Cook for an additional 2 minutes.
Remove from heat and serve garnished with chopped green onions.