Heat dutch oven and add olive oil.
Saute onion until soft, then add garlic and saute for 30 seconds.
Add tomatoes, and saute for a minute.
Then add stock, pasta, and season with salt and pepper.
Bring to boil, lower heat to medium low.
Cover and allow to cook for 7-8 minutes.
Uncover, and stir in spinach until wilted.
Remove from heat, and serve immediately.