Set a large Dutch oven or soup pot over medium heat.

Pull the meat from the rotisserie chicken until you have about 3 cups. Tear or cut it into bite-size pieces and set it aside.

Drain the cannellini beans in a colander, rinse them under cool water, and set them aside.

Add the olive oil to the hot pot.

Put the onion, carrots, celery, and 1/2 teaspoon of the salt into the pot.

Cook the vegetables over medium heat for 6 to 8 minutes, stirring a few times, until the onion looks soft and the carrots start to lose their raw edge.

Add the garlic and dried rosemary to the pot.

Cook for 30 seconds, stirring, until the garlic smells fragrant and does not brown.

Pour the chicken broth into the pot and scrape the bottom with a wooden spoon to loosen any browned bits.

Raise the heat to high and bring the broth to a boil.

Stir the drained beans into the pot.

Lower the heat to a gentle simmer and cook for 5 minutes so the beans warm through and the broth picks up some body.