In a large pot or Dutch oven, heat the olive oil over medium heat.
Add the diced onion and cook for 3 to 5 minutes, stirring occasionally, until it becomes soft and translucent.
Stir in the minced garlic, diced carrots, celery, potato, and green beans.
Cook for another 3 minutes, allowing the vegetables to soften slightly.
Add the basil, rosemary, water (or vegetable broth), tomato sauce, cannellini beans, and salt.
Stir everything together and bring the soup to a boil.
Once boiling, reduce the heat to low, cover the pot, and let it simmer for 15 minutes, or until the potatoes are just tender when pierced with a fork (al dente).
Add the diced zucchini to the pot and continue to simmer for about 5 more minutes, until all the vegetables are tender-crisp.
Taste the soup and adjust the seasoning with more salt and freshly ground black pepper if needed.
Serve hot and enjoy!
Don't be afraid to swap the veggies based on the season! Butternut squash in the fall or fresh peas in the spring would be delicious additions.