Creating delicious Italian Sausage White Bean Soup is straightforward if you follow these steps:

1. Cook the Sausage: In a large pot, heat a drizzle of olive oil over medium heat. Add the Italian sausage and cook until browned, breaking it up with a wooden spoon. Remove it from the pot and set aside.
2. Sauté Vegetables: In the same pot, add the diced onion, carrots, and celery. Sauté for about 5-7 minutes, or until the vegetables are softened. Add garlic and cook for another minute until fragrant.
3. Add Diced Tomatoes: Stir in the diced tomatoes with their juices, scraping up any brown bits from the bottom of the pot. This adds depth of flavor to the soup.
4. Combine Ingredients: Return the cooked sausage to the pot, then add the white beans, vegetable broth, Italian seasoning, and red pepper flakes (if using). Stir to combine everything well.
5. Simmer the Soup: Bring the mixture to a boil, then reduce the heat to low. Cover and let it simmer for 20-30 minutes to allow the flavors to intensify.
6. Add Greens: About five minutes before serving, stir in the kale or spinach. Cook until just wilted.
7. Season: Taste the soup and adjust seasoning with salt and pepper as needed.
8. Serve: Ladle the soup into bowls and garnish with grated Parmesan cheese and fresh parsley, if desired.

Enjoy the wonderful aromas filling your kitchen as this amazing soup comes together in no time!