Heat the oven to 350° F. Wash the eggplants and place on an oven dish. Bake the eggplants approx. 45 minutes in the oven until soft (check with a pointed knife). Let them cool and then halve them, scoop the flesh into a bowl and mash with a fork. Chop the onion, tomato and green pepper finely, crush the garlic, cut the capers a bit and mix all with eggplant. Add oil, vinegar, salt and pepper and let it sit for at least 30 minutes. Taste and if necessary add some salt and pepper.