Sauté Aromatics: Heat olive oil and butter in a large Dutch oven or soup pot over medium heat. Add diced onion and celery; cook for 5 to 6 minutes until tender and translucent. Add minced garlic, fresh rosemary, thyme, red pepper flakes, kosher salt, and black pepper. Sauté for 60 seconds until fragrant.

Add Beans & Broth: Pour in the rinsed cannellini beans and vegetable broth. Stir well, scraping up any fond from the bottom of the pot. Bring to a boil over medium-high heat.

Simmer: Reduce heat to medium-low, cover partially with a lid, and let the soup simmer gently for 15 minutes to allow the flavors to marry and the beans to soften.

Blend for Creaminess: To create a rich, velvety texture without adding excess cream, use an immersion blender to give 4 to 5 quick pulses directly in the pot (or transfer 1.5 cups of soup to a blender, puree until smooth, and pour back). This creates a luxurious naturally creamy base while leaving plenty of whole beans intact.

Finish with Greens & Cheese: Turn the heat to low. Stir in heavy cream, freshly grated parmesan cheese, and baby spinach. Simmer gently for 2 minutes until the spinach is wilted and the cheese is fully melted. Stir in fresh lemon juice and season to taste with additional salt and pepper if desired.

Ladle & Serve: Ladle the hot soup into warm shallow bowls. Garnish with a swirl of extra virgin olive oil, extra shaved parmesan, cracked black pepper, and fresh thyme leaves. Serve immediately with warm toasted sourdough bread.