Long purple aubergines (brinjals / eggplants) 200g (7oz)
Potato flour10g (⅓oz), mixed with a little water
Cooking oil for deep-frying
Sugar to taste
Place minced pork in a large mixing bowl. Add water chestnut, mushroom, ginger and egg. Mix ingredients in one direction until mixture starts to bind. Add salt and cooking wine and continue to mix in the same direction until well-mixed. Chill until ready to use.
Cut off aubergine stems. Using a meat slicer or mandolin, slice aubergine into thin slices lengthwise, starting from the ends, at a 45° angle.
Spoon about 8g (⅓oz) filling nearer to one edge of an aubergine slice. Roll up to enclose filling, leaving 6-cm (2.5-in) of the aubergine slice unrolled. Dab on some potato flour solution to seal rolled portion. Repeat for remaining aubergine slices and filling.
Heat cooking oil over low heat and deep-fry aubergine rolls until golden brown and cooked through. Drain on absorbent paper and arrange onto a serving plate. Reserve a little oil in wok.
Reheat reserved oil and sauté minced ginger until fragrant. Add water, vinegar and sugar and thicken mixture with potato flour solution. Pour sauce onto aubergine rolls and serve immediately.