Add the garlic and oregano and cook, stirring occasionally, until fragrant, about 2 minutes.
Stir in the tomato paste, mixing well, about 1 minute.
Add the broth and beans.
Increase the heat to medium-high and bring to a boil, then reduce the heat to medium.
Add the spinach and cook until it is wilted and the flavors have blended, about 10 minutes.
Season with salt and pepper.
Ladle the soup into warmed bowls and sprinkle with the Parmigiana Reggiano and serve immediately.
Notes
Be careful to only use 2 Tbs. of oil - oily soup is not a good thing.
If you are wondering what it would taste like if you substitute vegetable broth instead of chicken broth - I tried and it did not work for me. It changed the taste tremendously and my family did not like the change.
I use Amore tomato paste which comes in a tube. I buy mine at the grocery store. A big THANK YOU to Giada DeLaurentiis for mentioning this tube version on her show!
Recipe by Ladles of Yum at http://www.ladlesofyum.com/2012/07/florentine-white-bean-soup/