In a small pot, heat ½ tsp sesame oil. Add garlic, onion, and ginger. Sauté until fragrant (about 1 minute).
Pour in 2 cups beef broth. Stir in ½ seasoning packet, soy sauce, and oyster sauce. Bring to a simmer.
Add the noodles and cook according to package (about 3 minutes).
In the last minute, either: Crack an egg directly into the simmering broth for a poached effect, or Stir vigorously to create silky egg ribbons (egg-drop style).
Taste and adjust seasoning (add a splash of soy sauce if you like it saltier).
Serve hot, drizzle with a little more sesame oil, and top with green onions if you have them.