1 large onion, diced
- Cook the sausage and red pepper flakes in a Dutch oven over medium-high heat until crumbly, browned, and no longer pink, 10 to 15 minutes. Drain and set aside.
- Stir in the onions and garlic; cook until onions are soft and translucent, about 5 minutes.
- Pour the broth into the Dutch oven with the bacon and onion mixture; bring to a boil over high heat. Add the potatoes, and boil until fork tender, about 20 minutes. Reduce the heat to medium and stir in the heavy cream and the cooked sausage; heat through. Mix the spinach into the soup just before serving.