Remove sausage from casings and crumble it into a large stockpot. Cook over medium heat and add red pepper flakes, smoked paprika, onion, and garlic. Saute until the sausage is fully cooked, drain if necessary.
Add the chicken broth and Italian seasoning, increasing heat to high, and bring to a boil. Add diced potatoes. Cover pot, and reduce to simmer. Cook potatoes until tender.
While the potatoes are cooking, place milk, cream cheese, flour, and salt in a blender. Blend until smooth.
In a small saucepan, heat butter over medium-low heat, then add the milk mixture and cook over medium heat until thick (it should resemble a thick cream soup or pudding).
When the potatoes are cooked, add the thickened milk mixture and chopped baby kale to the stockpot. Season with additional crushed red pepper flakes and kosher salt to taste.