First of all, wash thoroughly all the vegetables. Soak rice in 2 cups of water. Chop the potatoes into wedges and dip them in cold water with a pinch of salt.
Now slice off the top of the tomatoes; using a spoon remove the flesh of the tomatoes and keep it in a bowl. (The flesh of the tomatoes will be the base for the tomato sauce for the Gemista.) Similarly slice off the top of the peppers and remove the seeds and white parts from the inside.
Place the empty vegetables on a large baking tray. Try to leave the vegetables as thin as possible, leaving just a little of the flesh, but be careful not to poke through their skin. Season the empty vegetables with a pinch of salt and sugar and add a little butter on the bottom of each one.
Cut the eggplant and zucchini in small cubes. Finely chop the garlic cloves and set aside, as we will use them later for the filling of the Gemista.
In a blender add the flesh of the tomatoes, 2 tbsps olive oil, the tomato puree, sugar, one teaspoon salt and pepper and mix to combine. Keep this aside, will use this as sauce for Gemista.
In a saucepan add one tablespoon of oil and sauté the onions, until translucent. Now add zucchini in the saucepan and sauté for one more minute. Now add chopped eggplant and chopped garlic and sauté, until softened. Add the rice and continue sautéing, until it becomes translucent. Pour in chopped tomatoes and add 1 teaspoon salt and 1/2 teaspoon pepper and mix well. As soon the liquid evaporates, the stuffing is ready. Add chopped mint and parsley and remove the pan from the stove.
Now lets do the final step of assembling the Gemista. Fill the stuffing inside the empty vegetables and place the potatoes wedges, in between the vegetables. Season with one teaspoon salt and 1/2 teaspoon of pepper and pour the tomato juice (sauce) over the vegetables and in the baking tray.
Cover the vegetables with their lids and add 1 glass of water.
Cover the Gemista with aluminium foil and bake in preheated oven at 180 degrees for 30 minutes. Then remove the aluminium foil and bake for more 30-35 minutes, until nicely coloured.
Garnish this with some mint leaves and cubed feta cheese and enjoy this greek delicacy in the privacy of your own home.