Here is the recipe of an Italian nonna*, you can just use it as it is or add some of your favourite vegetables.
• 2 tablespoons olive oil
• 1 medium onion, chopped
• 6 medium carrots, diced
• 6 celery stalks, chopped
• 2 medium zucchini, diced
• 3 ½ cup of water or vegetables or meat stock
1. In a large saucepan, heat the olive oil over medium heat.
2. Add the onions, carrots, celery, zucchini and sauté until the vegetables are softened.
3. Add the water or stock and cook during an hour until all the vegetables are cooked
4. Serve hot with freshly grated parmesan cheese
+Nonna's tip: add a bit of pancetta to give some extra flavour
++ You can also add some spices like garlic basilic, rosmary, etc. Potatoes and beans also taste really good in this soup. If you want a dish more consistent you may add some pasta or meat.
*nonna means grandma in Italian