Mix the cornflour into the bowl of cold water until no lumps remain. Add the light soy sauce and stir. Take the chicken and cover it in cling film on a chopping board and smash it out as thin as possible using a rolling pin. Trim off any excess fat. Cut into fine strips and add to the cornflour mix. Leave in the fridge to marinade for at least 30 mins.
Heat up a wok over a high heat and add some oil. Once hot, add the onion and allow to soften then pour off 90% of the marinade water from the chicken and pour the rest into the wok. Cook for 2-3 minutes then add in the crushed garlic and ginger and season with a pinch of white pepper and a tiny pinch of salt.
Turn the heat down to medium. Add in the whites of the spring onions and the sugar and stir. Crumble over the stock cube then add 2 cups of boiling water. Bring to a simmer.
After simmering for a minute add the fish sauce. Stir to combine. Add in the broccoli florets and simmer gently until 95% of the water has evaporated and reduced down.
Add in the oyster sauce. Stir it through gently to incorporate.
Serve up and garnish with the remaining greens of the spring onions. Enjoy!
