Toast the sesame seeds in a wok for 2–3 minutes until golden. Set aside.
Prep the scallions: slice the white parts into 5-cm strips and the green parts into thin rings. Soak the green rings in cold water.
Heat sesame oil in the wok and sauté the white scallion parts with the beef until it starts to brown, breaking it up into small bits.
Add garlic and ginger and stir until the beef turns grayish and fragrant.
Pour in soy sauce, hoisin sauce, brown sugar, stock (or water), chili flakes, and pepper. Cook for 1–2 minutes.
Add the noodles:
For soft noodles – soak briefly in boiling water before adding.
For firmer, chewier noodles – just drain and toss directly into the wok.
Mix well until everything is coated and glossy.
Finish with toasted sesame seeds, green scallion rings, and chopped cilantro.
Serve hot, and feel free to drizzle on more sauce if you like things extra juicy.
