Cut the stems from the leaves of Chinese broccoli. Combine the oyster sauce, garlic, soy and sugar in a small bowl.

Heat a wok over high heat until very hot. Add the oil and Chinese broccoli stems, stir fry for 30 seconds. Add 1 teaspoon water, quickly cover the wok. Steam 30 seconds, shaking the wok without removing the lid.

Remove the lid, add the leaves and oyster sauce mixture. Stir fry 30 seconds until leaves wilt. Remove from the heat. Arrange on a serving plate, spoon over the sauce in the wok. Drizzle over the sesame oil and top with shallots and chilli if desired.