In a large pot over medium heat, add the olive oil.
Brown the sausage until no longer pink.
Add the red pepper flakes, garlic, and onion and cook, stirring often, until the onions a translucent and the garlic is fragrant, about 4 minutes.
Add the chicken broth, potatoes, and kale.
Bring the broth to a simmer, reduce the heat to medium-low, and cook until the potatoes are tender, about 10 minutes.
Remove the soup from the heat, stir in the cream, and season with salt and pepper to taste.
Ladle into soup bowls and serve.