In a large, heavy bottom pot or dutch oven, heat olive oil on medium heat.
Add onions, and sauté them for 5-6 minutes.
Add chopped zucchini, carrots, fennel and celery and cook it for another 5-6 minutes. Take time to cook down the vegetables. Keep stirring in between. I like when vegetables caramelize a little bit. It adds more flavor.
Add the bay leaf, grated garlic, Italian seasonings, red chili flakes, black pepper and salt. Stir everything.
Add the tomato paste or diced tomatoes what ever you are using. If you are using whole peeled tomatoes, please crush them with your hands and then add them.
Add the boiled beans and 3 cups of water. Keep stirring in between.
Add a pinch of sugar to balance out the acidity of tomatoes. At this point, you can also add the parmesan rind to the soup. You can remove it once the soup is done.
Add chopped greens, whatever you are using.
Bring the soup to boil, then turn down the heat and let it simmer for another 10 minutes.
Taste and if needed add more seasonings. Adjust the consistency to your preference.
Stir in the fresh herbs like chopped basil, parsley or fennel fronds.
Serve it in bowls topped with crusty bread, drizzle of good olive oil and grated parmesan cheese.