Heat the olive oil in a large pot over medium heat. Add the diced onion and minced garlic, and sauté for 2-3 minutes until the onion is translucent and fragrant.

Add the carrots, celery, zucchini, and green beans to the pot. Cook for about 5 minutes, stirring occasionally, until the vegetables start to soften.

Stir in the white beans and diced tomatoes (including their juice). Pour in the vegetable broth, and add the dried oregano and basil. Season with salt and pepper to taste.

Bring the soup to a boil, then reduce the heat and let it simmer for about 10 minutes, or until the vegetables are tender.

Add the baby spinach leaves and cook for an additional 2 minutes, until the spinach is wilted.

Taste and adjust seasoning if needed. Ladle the soup into bowls and sprinkle with grated Parmesan cheese if desired.