Preheat the oven to 220C, fan-forced. Line an oven tray with baking paper. Thinly slice the spring onion on an angle. Coarsely chop the choy sum, keeping the stems and leaves separate. Shred the carrot using a julienne peeler or coarsely grate with a box grater.
Step 2 — Cook pork
Drizzle the pork with 2 tsp oil and season with salt and pepper. Heat a large deep frypan over high heat. Cook the pork, turning, for 4 mins or until browned. Transfer to the lined tray and reserve the pan. Spoon half the ayam goreng paste over the pork. Roast on the upper oven shelf for 11-13 mins until cooked to your liking. Remove from the oven and rest for 5 mins.
Step 3 — Make chilli oil
While the pork is roasting, bring a medium saucepan of water to the boil for the noodles. Heat 1 tbs oil in a small saucepan over medium-high heat until hot. Add ½ tsp chilli flakes* and half the spring onion and swirl the pan to combine. Remove the pan from the heat. Season with salt and pepper.
Step 4 — Cook noodles
Cook the noodles in the pan of boiling water for 2 mins or until tender. Drain, then rinse under hot water to prevent the noodles from sticking.
Step 5 — Finish noodles
Heat 2 tsp oil in the reserved frypan over medium-high heat. Stir-fry the choy sum stems and remaining ayam goreng paste for 1-2 mins until fragrant. Add the carrot, choy sum leaves, noodles, kecap manis and remaining spring onion to the pan and stir-fry for a further 1-2 mins until combined. Remove the pan from the heat.
Step 6 — Slice pork and serve
Slice the pork. Divide the stir-fried noodles and pork among plates and drizzle with the resting juices. Scatter over the peanuts and drizzle with the chilli oil to serve.