Heat the olive oil in a large Dutch oven or soup pot over medium-high heat. Add the ground Italian sausage, breaking it apart with a wooden spoon as it cooks until browned (about 5 minutes).

Add the diced onion to the pot with the sausage and sauté for 3-4 minutes until softened.

Stir in the minced garlic and red pepper flakes, cooking for 1 minute until fragrant.

Pour in the chicken broth, diced tomatoes (with their juices), and the drained cannellini beans. Bring the soup to a gentle boil.

Reduce the heat to low and stir in the chopped kale. Let the soup simmer for 5 minutes until the kale is tender and wilted.

Taste the broth and season with salt and black pepper as needed.

Ladle into warm bowls, top with freshly grated parmesan cheese, and serve immediately with crusty bread.