In a large pot, heat olive oil over medium heat.
Add the chopped onion and sauté until translucent.
Stir in minced garlic and cook for an additional minute.
Add the Italian sausage, breaking it apart with a wooden spoon, and cook until browned.
Incorporate the diced potatoes and chicken broth, bringing the mixture to a boil.
Reduce the heat and let it simmer until the potatoes are tender, about 15 minutes.
Stir in the chopped kale and let it cook for another 5 minutes.
Pour in the heavy cream and mix well.
Season with salt, pepper, and red pepper flakes to taste.
Serve hot, garnished with additional kale if desired.