In a frying pan, put some oil and lightly fry the eggplant pieces. Remove them from the pan.
Using the same fry pan, add some oil. Then, add the cumin seeds and chopped garlic. Fry for 15 seconds, then add the onion and red pepper flakes. Fry for 3 minutes. Add the eggplants and stir it. Add the ketchup and mix it well.
Add the vinegar and mix it. Cover the pan and keep on low heat for 8 minutes. Take off the lid, then add the salt and a little bit of water (if necessary). Cook for 4 minutes without the lid.
Sprinkle the coriander over and turn off the heat.