Wash eggplants and cut into large cubes. Fry in 2/3 of the olive oil until brown. Transfer to a large baking dish. Cut the onions into rings, sauté in the remaining oil, squeeze in the garlic. Add to the aubergines, salt and pepper. Drain the chickpeas well and add them to the baking dish. Mix everything well with the tomato pieces and the tomato puree. Season well with garam masala, salt, pepper and cayenne pepper.
Cook in the oven at 175 degrees (convection) for about 30 minutes. Serve with flatbread and garlic yogurt.
I prefer to eat the casserole lukewarm. Like all casseroles, it tastes best when it is reheated.