Brown sausage in a large pot or dutch oven. Remove sausage with a slotted spoon and set aside.
Cut bacon into small pieces. Add bacon to pot and cook until crispy.
Stir in chopped onion. Cook for 5 to 6 minutes or until onion is translucent.
Stir in minced garlic and cook for 1 minute, stirring frequently.
Add chicken broth and water to the pot. Add crushed red pepper flakes, salt, and pepper if desired.
Add thinly sliced potatoes (I use a mandoline) and the cooked sausage to the pot and bring to a simmer over medium heat.
Continue cooking until potatoes are tender, about 10 minutes.
Add the kale to the soup, and simmer for an additional 5 to 10 minutes, stirring occasionally. Test for seasoning and season with salt and pepper if needed.
Stir in the heavy cream and let heat through.
Ladle the soup into bowls and serve with Parmesan cheese on top.