Cut the tops off 8 tomatoes, 4 green bell peppers, and 2 eggplants and keep them as lids. Scoop out the tomato flesh for the sauce, seed the peppers, and scoop out and dice the eggplant flesh.
Arrange the shells in a large baking dish. Season inside with salt and a pinch of sugar, and divide 2 tablespoons of butter among them.
Blend the tomato flesh with 6 tablespoons of olive oil, 2 tablespoons of tomato paste, 2 teaspoons of sugar, salt, and pepper.
Preheat the oven to 350°F / 180°C. Soften 2 finely chopped red onions in a little olive oil. Add 1 finely chopped zucchini, the diced eggplant, and 2 minced garlic cloves and cook until soft.
Stir in 500g of risotto rice until translucent. Add 400g of canned chopped tomatoes and 2 cups of water and boil for 5 minutes; the rice should stay firm.
Stir in 1 small bunch of chopped parsley and 1 small bunch of chopped mint. Fill the vegetables two-thirds full, top up with the tomato sauce and the rice liquid, and replace the lids.
Tuck 5 potatoes, cut into wedges, between the vegetables and season. Pour any leftover filling and sauce into the dish with 3 cups of water.
Cover with aluminum foil and bake for 60-75 minutes, removing the foil halfway through.
