Bring a medium saucepan of water to the boil for the noodles and peas. Halve the carrot lengthwise and thinly slice. Slice the choy sum, keeping the stems and leaves separate. Thinly slice the spring onion. Crush or finely chop the garlic. Peel and finely grate the ginger.
Step 2 — Make oyster-soy sauce
Combine the oyster sauce, 1 tbs water and 2 tsp soy sauce in a bowl.
Step 3 — Prep and stir-fry chicken
Thinly slice the chicken into strips. Combine the chicken, cornflour and 1 tsp soy sauce in a bowl. Heat 2 tsp oil in a medium deep frypan over high heat. Stir-fry the chicken for 4 mins or until golden and cooked through. Remove from the pan.
Step 4 — Stir-fry vegetables
Heat 2 tsp oil in the same pan over high heat. Stir-fry the carrot, choy sum stems, spring onion, garlic and ginger for 2 mins. Add the oyster-soy sauce and choy sum leaves and cook, stirring, for 1 min or until the vegetables are just tender.
Step 5 — Cook noodles and peas
While the vegetables are cooking, add the noodles and peas to the pan of boiling water, return to the boil and cook for 2 mins or until tender. Drain, then rinse under hot water to prevent the noodles from sticking.
Step 6 — Get ready to serve
Add the noodles, peas, chicken and any resting juices to the stir-fried vegetables and cook, tossing, for 1 min or until combined and heated through. Divide the noodle stir-fry among bowls to serve.