Step 1: Heat the olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion and cook until softened and translucent, about 5-7 minutes.
Step 2: Stir in the minced garlic, chopped sun-dried tomatoes, Italian seasoning, and red pepper flakes (if using). Cook for another 1-2 minutes until fragrant.
Step 3: Pour in the vegetable broth and add the rinsed cannellini beans. Bring the soup to a simmer. Use the back of a spoon or a potato masher to mash about 1/3 of the beans against the side of the pot. This will help thicken the soup and create a creamy texture.
Step 4: Reduce heat to medium-low, cover, and let the soup simmer for 15-20 minutes, allowing the flavors to meld. Stir occasionally.
Step 5: Stir in the heavy cream, chopped kale, and grated Parmesan cheese. Cook for another 3-5 minutes, or until the kale has wilted and the soup is heated through.
Step 6: Taste the soup and season with salt and freshly ground black pepper as needed. If the soup is too thick, add a little more broth until desired consistency is reached.
Step 7: Ladle the Creamy Tuscan White Bean Soup into bowls. Garnish with additional Parmesan cheese and fresh basil or parsley, if desired. Serve hot with crusty bread.