Prepare and wash eggplants and zucchini. Cut vegetables into 2-finger thick rings. Prepare and wash the peppers. If peppers are horn-shaped, cut into two long thin slices lengthwise. Salt lightly. Peel the potatoes and onions. Preheat oven at 200oC. In a bowl, cut onion into small cubes, add the grated tomato, parsley, garlic, some more salt, pepper, and half the olive oil (optionally you can also add wine). Mix or knead with your hands so ingredients combine well. Layer the bottom of a baking dish with the vegetables, add another layer with the sliced potatoes and tomatoes cut into large cubes. Pour tomato sauce over vegetables and add the rest of the olive oil. Cover the briam with aluminum foil and place dish on the rack on the first position up from the bottom. Remove aluminum foil in an hour having checked before if all water has been absorbed. Continue baking for another 50-60 minutes or until vegetables have softened and sauce has thickened. Serve hot, warm or at room temperature with feta cheese, another soft cheese or yoghurt. Briam is a traditional dish, which is suitable for all occasions.