In a dutch oven or heavy saucepan, add onion and butter and sautee until onion is transparent, about 3 minutes.
Add sausage and continue to cook until edges begin to brown. About 3 minutes.
Add chicken broth, stewed tomatoes (with juice), oregano, and basil. Bring to a boil.
Add pasta and continue with a rolling boil. Reduce heat to a slow boil and cover. Cook for 8-12 minutes or until pasta is done. Add salt and pepper to taste.
Add 1 cup spinach and stir until wilted.
Serve with shredded Parmesan cheese.