We heat water in a large saucepan and bring it to a boil. We remove the hard part of the tomatoes and make a cross cut at the base. We introduce them in the boiling water for about 15-20 seconds, remove them and put in a bowl of ice water. We peel and grind them.
Peel the garlic cloves and onion and finely chop them. We wash the rest of the vegetables well and cut them into small pieces of equal size. We reserve them separate from each other as we will add them to the casserole in different phases.
Heat a generous amount of extra virgin olive oil in a saucepan and sauté the minced garlic and onion for 15 minutes over low heat. Add the chopped pepper and sauté for 15 more minutes. Finally we add the zucchini and the crushed tomato, season to taste, cover and let poach for a minimum of an hour and a half.
After this time, we remove the lid from the casserole, raise the heat a little and cook for 15 more minutes or until the tomato water has evaporated. We want it to be juicy, but no traces of the water released by the vegetables, with all the ingredients well amalgamated. once this consistency is achieved, we serve immediately.