In a large pot, heat the olive oil over medium-high heat. Add the diced onion and sauté until translucent, about 3-4 minutes. Add the minced garlic and cook for an additional 30 seconds. Stir in the cauliflower florets, drained beans, vegetable broth, water, Italian herb blend, salt, and pepper. Bring to a boil, then reduce heat to low, cover, and simmer until the cauliflower is fork-tender, approximately 12 minutes. Use an immersion blender to puree the soup, leaving some chunks of cauliflower and beans. Alternatively, blend in batches using a traditional blender. Return the soup to the pot and stir in the grated parmesan cheese. Adjust seasoning if needed.

Serve hot with a drizzle of olive oil, lemon wedges, chili flakes, or pesto for added flavor. Fresh bread complements this soup perfectly.