Heat olive oil in a large pot over medium heat
Add Italian sausage and cook until browned, breaking it into crumbles
Remove excess grease if needed
Add chopped onion and cook until softened
Add minced garlic and cook briefly until fragrant
Pour in chicken broth
Add sliced potatoes
Bring to a boil, then reduce heat and simmer until potatoes are tender
Stir in chopped kale and cook until wilted
Add heavy cream and stir to combine
Season with salt, black pepper, and red pepper flakes to taste
Simmer a few more minutes
Serve hot