Add Garlic and Other Vegetables: Stir in the minced garlic, zucchini, and bell pepper. Cook for another 3-4 minutes, stirring frequently.
Add Tomatoes and Broth: Pour in the diced tomatoes and vegetable broth. Bring the mixture to a simmer.
Add Beans and Seasonings: Stir in the cannellini beans, green beans, dried basil, dried oregano, red pepper flakes (if using), and season with salt and black pepper.
Simmer: Reduce the heat to low and let the soup simmer for 20-25 minutes, allowing the flavors to meld and the vegetables to cook through.
Add Greens: In the last few minutes of cooking, add the fresh spinach or kale and stir until wilted.
Serve: Ladle the soup into bowls and top with grated Parmesan cheese and chopped fresh parsley if desired.