In a large pot or Dutch oven over medium heat, cook the chopped bacon until crispy. Remove with a slotted spoon and set aside. In the same pot, add the Italian sausage, breaking it into crumbles as it cooks. Once browned, remove and drain excess grease, leaving about 1 tablespoon for added flavor.
Add diced onion to the pot and sauté for 3-4 minutes until softened. Stir in the minced garlic and cook for an additional 30 seconds until fragrant.
Pour in the chicken broth, scraping up any browned bits from the bottom of the pot for extra flavor. Add the thinly sliced potatoes, salt, black pepper, and crushed red pepper flakes. Bring to a boil, then reduce the heat and let it simmer for about 15 minutes, or until the potatoes are tender.
Once the potatoes are soft, stir in the heavy cream and fresh kale. Let it simmer for another 5 minutes until the kale is wilted and the soup is creamy.
Ladle the soup into bowls and top with crispy bacon crumbles, grated Parmesan cheese, and additional red pepper flakes if desired. Serve hot with warm breadsticks or crusty bread.