1. Heat 2 teaspoons oil in a large pot over medium heat. Crumble sausage into pan. Using a wooden spoon, break up sausage into small pieces. Cook until no pink remains, around 5 to 6 minutes and transfer to a bowl.
2. Add remaining 2 teaspoons oil to same pot, and then add onion, carrot, celery and salt. Cook, stirring often, until onion is soft, 6 to 7 minutes. Stir in sausage, chicken broth, water and beans. Boil, and then reduce heat to medium-low and simmer, covered, for 5 minutes.
3. Stir in pasta, kale and tomato paste. Increase heat to medium-high and continue cooking until pasta is tender, about 10 minutes.

Photo by Roberto Caruso