In a large Dutch oven or soup pot (approximately 5.5 quarts), warm over medium-high heat and add the chopped bacon, cooking until crisp and browned, about 5–7 minutes. Transfer the bacon to a plate lined with paper towels and carefully drain excess fat, leaving about 1 tablespoon of rendered fat in the pot. Add the Italian sausage, breaking it apart with a spatula, and sauté until thoroughly cooked, about 5 minutes, then set aside on a paper towel–lined plate. Add the finely diced onion to the pot and cook for 5 minutes until softened and lightly golden, then stir in the minced garlic and cook for an additional minute until fragrant. Pour in the chicken broth and water, bringing the mixture to a boil. Add the sliced potatoes and cook for 13–14 minutes, or until they can be easily pierced with a fork. Once the potatoes are nearly tender, return the cooked sausage to the pot and stir in the chopped kale, allowing the soup to reach a gentle boil. Pour in the whipping cream and bring the soup to a final boil, seasoning generously with salt and freshly ground black pepper. Remove from the heat and garnish with the reserved crispy bacon and a sprinkling of Parmesan if desired.