Cook the eggplants in a pre-heated moderate oven, 180C/350F, for 30 minutes or until soft. Cool slightly, then slit open, scoop out all the flesh and beat it with a fork. Heat the oil in a pan, add the onion, garlic and chilli and fry until the onion is soft but not coloured. Add the ground and fresh coriander and salt to taste. Add the eggplant pulp, stir well and fry, uncovered, for 2 minutes, then cover and simmer very gently for 5 minutes. Sprinkle with lemon juice and serve.