Place pasta, tomatoes, sun dried tomatoes, onion, garlic, and basil in a large stock pot.
Pour in vegetable broth. Sprinkle the pepper flakes and oregano on top.
Drizzle with olive oil.
Add 1/2 teaspoon salt and some ground black pepper.
Cover pot and bring to a boil. Reduce to a low simmer and cook for about 10 minutes (add the spinach 7 to 8 minutes into cooking), stirring every 2 minutes. Cook until almost all of the liquid has evaporated.