Pour the broth into the pan, add the chopped tomatoes and bring to a boil, then reduce the heat.
Peel the carrots, cut into circles and pour into the pan. Simmer over low heat until carrots are tender, about 15 minutes.
Drain the liquid from the cans of beans, rinse the spinach under running water. Add bean mixture and spinach to soup. Cook 4-5 minutes until the spinach is wilted.
Add a spoonful of pesto and mix gently. Serve with toast or croutons.