Add the diced tomatoes, beans, tomato sauce, vegetable broth, basil, parsley, oregano, salt and pepper. Stir together and let come to a low boil. Once boiling, turn down the heat to low and let simmer for 15 minutes.
Add spinach and dried pasta shells. Let cook until pasta is done. About 10 minutes, depending on what size pasta you use.
** Leftovers will soak up the broth so you will probably want to add additional water or broth when reheating leftovers.
If you want a thinner soup then use 4 cans of vegetable broth instead of 3. I love a soup that is not super brothy so I use 3 cans. The soup does thicken up as it sits (after cooking) so leftovers will not have much broth. Add water or additional broth when reheating.
An easy way to get thinly sliced carrots is to use baby carrots. They are already peeled, and small so all you have to do is slice them.
I like to chop up the spinach into smaller pieces. You can do this or just throw the spinach in as is.