Cook noodles – If using dried noodles, cook according to package instructions until just tender. Drain, rinse, and set aside. For fresh noodles, flash-boil for 30–60 seconds, drain.
Make the sauce – In a small bowl, mix oyster sauce, soy sauce, kecap manis (or sugar), and broth. Set aside.
Cook the pork or chicken - Heat 1 tbsp of oil in a large wok or skillet over medium-high heat. Add the sliced pork or chicken. Stir-fry for 2–3 minutes (chicken) or 3–4 minutes (pork) until browned and mostly cooked through. Push the meat to one side of the wok. Add the remaining 1 tbsp oil if needed.
Stir-fry aromatics – Heat oil in a large wok over medium-high heat. Add garlic and shallots, stir-fry until fragrant and lightly golden (30–45 seconds). Mix with the pork or chicken.
Add kangkung – Toss in the chopped kangkung and stir for 1–2 minutes until it starts to wilt but stays crisp.
Combine noodles and sauce – Add the cooked noodles to the wok, pour the sauce mixture over, tossing quickly to coat. If it looks dry, splash in more broth.
Thicken – Stir the cornstarch slurry, drizzle it into the wok, and toss until the sauce becomes glossy and clings to the noodles (30–60 seconds).
Finish and serve – Season with pepper and extra soy or kecap manis to taste. Garnish with fried shallots, spring onion, and a squeeze of lime.
