To Prep
Marinate chicken in corn flour, dry sherry and ginger for 30 mins.
Wash and cut Chinese mustard, discarding any old or tough leaves.
To Cook
Heat ½ tbsp oil in a wok, add garlic and Chinese mustard, stir-fry for 2 mins. Remove from wok.
Heat remaining oil in a wok and stir-fry chicken for 5 mins.
Add oyster sauce and vegetables, combine well.
Serve with rice or noodles.