Saute the onions in a large stock pot or Dutch oven with olive oil from the sun-dried tomatoes jar and olive oil.
Add tomatoes, garlic, and tomato paste; cook for another two minutes.
Combine broth, Italian seasoning, garlic powder, salt, and pepper; bring to a simmer.
Add chicken, spinach, and pasta to the soup; simmer for about 10 minutes.
Temper hot milk with broth, then stir into the soup along with grated Parmesan cheese.
Serve the soup with extra Parmesan cheese on top.
