Heat olive oil in a large pot over medium heat. Sauté onion and garlic until fragrant.
Add canned tomatoes, dried oregano, salt, and pepper. Stir and let simmer for 2 minutes.
Pour in pasta and water (or broth). Stir well and bring to a gentle boil.
Cook uncovered for about 10–12 minutes, stirring occasionally until pasta is al dente.
Stir in cream, spinach, and Parmesan. Cook for 2–3 minutes until spinach wilts and sauce thickens.
Taste and adjust seasoning, then serve hot with extra Parmesan on top.