01 - Heat olive oil in a large soup pot over medium heat. Add the sausage, breaking it into crumbles with a wooden spoon. Cook until evenly browned, approximately 5 minutes. Transfer to a plate and set aside.
02 - In the same pot, cook the diced onion until translucent, about 3 to 4 minutes. Add the minced garlic and stir for 1 minute until fragrant.
03 - Add the sliced potatoes and chicken broth to the pot. Bring to a boil, then reduce heat and simmer uncovered for 12 to 15 minutes until the potatoes are fork-tender.
04 - Stir in the chopped kale and the reserved browned sausage. Simmer for an additional 5 minutes until the kale is wilted and tender.
05 - Reduce heat to low. Pour in the heavy cream and stir gently. Season with red pepper flakes, salt, and black pepper to taste. Heat through without boiling to preserve the creamy texture.
06 - Ladle into warmed bowls and garnish with grated Parmesan cheese if desired. Serve immediately with crusty bread alongside.