Clean the Chinese broccoli, discarding any tough or old leaves. Slice the stems thinly on a diagonal and set aside. Bring a large bowl of water to a boil, add a little cooking oil, then add the stems to blanch first. After a few moments, add the leaves and stir. Turn off the heat.

Drain the blanched vegetables in a colander. Smash the ginger and garlic, then add them to a hot pan with oil. Add the vegetables and stir-fry quickly over high heat to keep them green. Add the oyster sauce, 1 tablespoon cold water, and a pinch of sugar, mixing well. Just before turning off the heat, add 2 teaspoons white wine and stir to combine.