Cook the chestnuts in simmering water for about 45 minutes, or until tender, then drain. Blanch the cabbage in boiling water for 2 minutes, then refresh in iced water and drain on paper towel.
Heat the oil in a wok or deep-fryer until just smoking (180°C/350°F), and deep-fry the cabbage in two batches until golden. Remove with a slotted spoon and drain on paper towel. Deep-fry the chestnuts in the same oil for 2–3 minutes, then drain on paper towel. Discard all but
Return the wok to the heat and reheat until smoking. Stir-fry the ginger and spring onion until fragrant. Deglaze the wok with the shaoxing, and then add the salt, sugar, both soy sauces and chicken stock. Return the cabbage and chestnuts to the wok and stir-fry over high heat until the sauce boils and reduces by about half. Transfer to a bowl to serve.