Risotto alle verdure

Clean and wash all the vegetables and cut into small cubes (except tomatoes) and set aside. Cut the tomatoes into wedges and place in a bowl with a teaspoon of sugar, so that they lose their acidity. Put half of the chopped onion in a pan with three tablespoons of olive oil and the butter on a low heat and let it sweat. When the onion becomes transparent (it will take about 15 minutes), add all the diced vegetables to the pan (zucchini, half quantity of carrots, eggplants, peas and peppers). Add salt and pepper, and cook the vegetables for about 15 minutes. The vegetables should be soft but not soggy. In another pan, prepare a classic Italian soffritto, sauté the chopped celery, the other half of the onion and carrot. Add the rice and sauté for 2-3 more minutes until rice grains are translucent, then pour in the white wine and keep stirring to cook out the alcohol. At this point, start adding warm stock, a ladleful at a time, stirring often. Half-way through the cooking process, add the other vegetables (except the tomatoes) and keep stirring. Add more stock as needed, until the rice is cooked "al dente". Turn off the heat, stir in the tomatoes wedges, the remaining butter and serve with grated Parmesan cheese, chives and freshly ground pepper.