Put some water in a pan and bring it to the boil. Slice the aubergines and place them in a steamer. Steam them for about 10 minutes – to check whether they’re ready, simply squeeze the sides gently and if they’re silky soft then they’re done. Remove them from the steamer, place them in a colander and leave to cool.
Wash greens carefully and remove stems. Chop leaves into bite size pieces. Heat a large skillet over medium heat. Add olive oil. Add greens and toss to coat with oil. Sauté over medium heat until leaves begin to turn brilliant green and wilt down. Mix together 1 tablespoon apple cider vinegar (or mirin), and 2 tablespoons of water. Pour into pan. Cover pan tightly. Cook until leaves are tender, 5 to 8 minutes, adding 1 to 2 tablespoons of water if pan becomes dry. Taste to check and add salt. Greens should be tasty, not bitter; still green, and not grey.