In a soup pot, add the olive oil, ground sausage, and onion. Cook over medium heat till the sausage is no longer pink and onion softens.
Add garlic and stir.
Add potatoes and broth. Simmer soup over medium heat until potatoes are fork tender, about 8-10 minutes.
Add the cream, spinach, pepper, and red pepper flakes. Stir. Allow soup to continue simmering till the spinach is wilted and reduced in size. Season with salt if desired. Serve.