01 - Heat olive oil in a large soup pot over medium heat. Add the Italian sausage, breaking it into crumbles with a wooden spoon. Cook until evenly browned, approximately 5 minutes. Transfer the sausage to a plate and set aside.
02 - In the same pot, add the diced onion and cook until translucent, about 3 to 4 minutes. Stir in the minced garlic and cook for an additional minute until fragrant.
03 - Add the sliced potatoes and chicken broth to the pot. Bring to a boil, then reduce the heat and simmer uncovered for 12 to 15 minutes until the potatoes are just tender when pierced with a fork.
04 - Return the browned sausage to the pot and add the chopped kale. Simmer for an additional 5 minutes until the kale has wilted and is tender.
05 - Reduce the heat to low. Stir in the heavy cream and season with crushed red pepper flakes, salt, and black pepper to taste. Heat through gently, but do not allow the soup to boil.
06 - Ladle the soup into bowls and garnish with grated Parmesan cheese if desired. Serve immediately with crusty bread.