Heat the olive oil in a large pot over medium heat.
Add the sausage and cook, stirring, until browned, about 5 minutes.
Add the onion, garlic, carrots, and celery. Cook, stirring, until the vegetables are tender, about 5 minutes.
Add the chicken broth, potatoes, oregano, basil, salt, and pepper. Bring to a boil, then reduce the heat and simmer until the potatoes are tender, about 15 minutes.
Add the spinach and stir until wilted, about 2 minutes.
Serve hot.
Interesting Facts
This soup is a great way to use up any leftover potatoes you may have.
You can substitute other types of sausage, such as chorizo or kielbasa, for the Italian sausage if desired.
This soup can be made ahead and reheated for an easy meal.