Warm olive oil and butter in a large Dutch oven or soup pot over medium heat. Add the diced onion, carrots, and celery. Sauté for 6 to 7 minutes until the vegetables soften and begin to sweeten.

Stir in the minced garlic, chopped fresh rosemary, thyme, red pepper flakes, sea salt, and black pepper. Cook for 60 seconds until delightfully fragrant, stirring constantly to prevent the garlic from scorching.

Add the drained cannellini beans, vegetable broth, and the Parmesan cheese rind (if using) into the Dutch oven. Stir well and bring to a lively boil over medium-high heat.

Reduce heat to medium-low and simmer uncovered for 10 minutes to allow the beans to absorb the aromatic herb broth.

Remove and discard the Parmesan rind. Use an immersion blender directly in the pot to blend about one-third to one-half of the soup until luscious and creamy, leaving plenty of whole tender beans and vegetables for satisfying texture. (Alternatively, ladle 2 cups of soup into a blender, purée until smooth, and stir back into the pot).

Turn heat to low. Stir in the fresh baby spinach, grated Parmesan cheese, and fresh lemon juice. Simmer gently for 2 minutes until the spinach wilts into vibrant emerald ribbons and the cheese melts seamlessly into the broth.

Ladle into warm bowls. Garnish with a swirl of peppery extra virgin olive oil, extra grated Parmesan, cracked black pepper, and serve alongside crusty artisan sourdough bread.