To a large saucepan, add the onion and carrots and saute them in the olive oil for a few minutes. Pour in the chicken stock, crushed tomatoes and frozen spinach and bring to bubbling. Add the meatballs, basil, and thyme, then the small shell pasta.
(Note: if making your own meatballs, you'll need to brown them in a skillet before adding them to the soup.)
Let cook over medium low heat, at rolling boil until pasta is cooked, about 8 minutes. If cooking raw meatballs, simmer until meatballs are cooked through.
Season with salt and pepper to taste.
Serve Italian Meatball Soup.