Heat 2 tablespoons of olive oil in a large pot or Dutch oven over medium heat. Add the diced onion, carrots, and celery (this is the 'soffritto'). Cook, stirring occasionally, until the vegetables have softened and the onion is translucent, about 8-10 minutes.

Add the minced garlic, chopped rosemary, thyme leaves, and red pepper flakes (if using). Stir constantly and cook for 1 minute more until fragrant.

Pour in the vegetable broth and the undrained diced tomatoes. Add the rinsed cannellini beans and the bay leaf. Stir to combine, scraping up any browned bits from the bottom of the pot.

Increase the heat to bring the soup to a boil, then reduce the heat to low, cover the pot, and let it simmer for at least 20 minutes to allow the flavors to meld together.

Remove and discard the bay leaf. To create a creamy base, use an immersion blender to pulse the soup directly in the pot 4-5 times. This should blend about one-third of the soup while leaving plenty of whole beans and vegetables for texture. (Alternatively, carefully ladle 2 cups of soup into a blender, blend until smooth, and pour it back into the pot).

Stir in the chopped kale. Let the soup continue to simmer for another 5-7 minutes, or until the kale is tender and wilted to your liking.

Turn off the heat and stir in the fresh lemon juice. This brightens all the flavors. Taste the soup and season with kosher salt and black pepper as needed.

Ladle the hot soup into bowls. Drizzle generously with high-quality extra virgin olive oil and a sprinkle of grated Parmesan cheese. Serve immediately with crusty bread for dipping.