Julienne the onion and thinly slice the garlic. Chop 2 large sprigs of basil.
Place the uncooked pasta, tomatoes with juice, onion, garlic, basil, in a large stock pot. Pour in vegetable broth. Sprinkle on top the 1/2 teaspoon pepper flakes and oregano. Drizzle top with oil.
Cover pot and bring to a boil. Reduce to a low simmer and keep covered and cook for about 10 minutes, stirring every 2 minutes. Cook until almost all liquid has evaporated – leave about an inch of liquid in the bottom of the pot.
Season to taste with salt and pepper, stirring pasta several times to distribute the liquid in the bottom of the pot. Serve garnished with Parmesan cheese.