In a large pot, break the sausage into pieces and cook over medium heat until browned. Add the onion and garlic and cook for another 5 minutes, until slightly softened.
Add the chicken broth and beans to the pot, season with salt and pepper, and bring the liquid to a simmer. Cook for 15 minutes or until the beans are heated through.
Stir in the kale and vinegar and cook for another 2 minutes, until the kale is wilted but still bright green.
Chill, cover, and store leftovers in the fridge for up to 3 days.
Notes
Want a spicier soup? Use hot Italian sausages and consider adding a pinch of red chili flakes to really turn up the heat.