Brown the sausage. In a large pot or Dutch oven over medium heat, cook the sweet Italian sausage until browned, breaking it apart with a spoon.
Sauté aromatics. Add diced onion and minced garlic to the pot. Stir and cook until the onion becomes soft and fragrant.
Add potatoes and seasoning. Stir in the sliced red potatoes, Italian seasoning, red pepper flakes, salt, and black pepper
Simmer. Pour in the chicken bone broth, stir to combine, then cover and bring to a gentle simmer. Lower the heat and cook for about 10 minutes, or until the potatoes are tender.
Add cream and kale. Reduce heat to low, stir in the heavy cream and chopped kale. Cover and cook for another 4 minutes, until the kale softens and the soup turns creamy.
Serve. Taste and adjust seasoning as needed. Serve warm with crusty bread or a sprinkle of parmesan on top, if desired