Bring a medium saucepan of water to the boil for the noodles. Thinly slice the onion and capsicum. Halve the carrot lengthwise and thinly slice on an angle. Coarsely chop the pak choy, keeping the leaves and stems separate. Peel and finely grate the ginger. Crush or finely chop the garlic.
Step 2 — Prep sauce
Put the oyster sauce, half the sesame oil*, 1 tbs soy sauce, 2 tsp white vinegar and 2 tsp honey in a bowl and whisk to combine.
Step 3 — Prep chicken
Thinly slice the chicken into strips. Put the chicken in a bowl, add the cornflour and toss to coat.
Step 4 — Make stir-fry
Heat 2 tsp oil in a large frypan over high heat. Stir-fry the chicken for 2-3 mins until golden and cooked through. Remove from the pan. Add 2 tsp oil to the same pan and heat until hot. Stir-fry the onion, capsicum and carrot for 3-4 mins until just tender. Add the ginger and garlic and stir-fry for a further 30 secs or until fragrant.
Step 5 — Cook noodles
Meanwhile, 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 6 — Get ready to serve
Add the pak choy stems and sauce to the stir-fry and cook, stirring, for 1 min. Add the pak choy leaves and chicken and cook, stirring, for 30 secs or until combined. Add the noodles and toss to combine. Divide the stir-fry among bowls and scatter with the sesame seeds to serve.