Heat olive oil in a large pot over medium heat.
Add the crumbled Italian sausage and cook until browned.
Remove the sausage and set aside, leaving the drippings in the pot.
Add the chopped onion to the pot and sauté until translucent.
Stir in the minced garlic and cook for 1 minute.
Add the diced potatoes and chicken broth to the pot.
Bring to a boil, then reduce heat and simmer until potatoes are tender.
Return the sausage to the pot along with the heavy cream.
Add the chopped kale and cook until wilted.
Season with salt, pepper, and red pepper flakes to taste.