In a large soup pot or Dutch oven, brown the sausage over medium-high heat, breaking it into crumbles. Remove sausage and set aside, leaving about 1 tablespoon of drippings in the pot.
Sauté the onion until softened, about 5 minutes. Add garlic and cook 1 minute, until fragrant.
Add chicken broth, beans, diced tomatoes (with juices), Italian seasoning, and red pepper flakes. Bring to a boil, then reduce heat to medium-low and simmer 10-15 minutes.
Stir in the cream and kale. Cook until kale is wilted and tender, about 5 minutes.
Return cooked sausage to the pot. Season with salt and pepper to taste.
Serve hot with freshly grated Parmesan and extra red pepper flakes, if desired.
Notes
Let the soup cool completely, then store it in an airtight container in the refrigerator for up to 3 days.
Reheat it gently on the stovetop over medium-low heat, stirring occasionally. You can also reheat individual bowls in the microwave, stopping to stir so it heats evenly.
To freeze, let the soup cool completely, then transfer it to freezer-safe containers. Freeze for up to 2 months. Thaw overnight in the refrigerator and reheat gently, stirring well as it warms.