Place a large Dutch oven over medium-high heat. Add the chopped bacon and sauté until crisp, approximately 5-7 minutes. Remove bacon with a slotted spoon and drain on paper towels, reserving 1-2 tablespoons of fat in the pot.
Add the ground Italian sausage to the pot. Cook until browned and fully crumbled, about 7-10 minutes. Remove the sausage and drain on paper towels.
Add the diced onion to the reserved fat in the pot. Sauté for 5 minutes until translucent. Add the minced garlic and red pepper flakes, cooking for 1 minute until fragrant.
Pour in the chicken broth and water. Use a wooden spoon to deglaze the bottom of the pot, scraping up any browned bits (fond).
Add the sliced potatoes to the liquid. Bring to a boil, then reduce heat to medium-low. Simmer for 15 minutes or until the potatoes are tender when pierced with a fork.
Stir in the cooked sausage and the chopped kale. Simmer for 3-5 minutes until the kale has wilted and turned bright green.
Reduce heat to low and stir in the heavy whipping cream. Heat through for 1-2 minutes without reaching a boil to prevent curdling.
Season with salt and black pepper to taste. Ladle into bowls and garnish with the reserved crispy bacon and grated Parmesan cheese.