Brown sausage in a large pot or Dutch oven over medium-high 5-7 minutes, breaking up with a wooden spoon.
Cook onion 3 minutes until softened; add garlic and cook 30 seconds until fragrant.
Add tomatoes with juices, broth, and Italian seasoning; bring to a boil.
Stir in pasta; reduce heat to medium, cover, and cook 12-15 minutes, stirring occasionally, until tender.
Stir in spinach; cook 1-2 minutes until wilted.
Off heat, stir in Parmesan; season with salt and pepper and serve immediately with extra Parmesan if desired.