In a large pot or Dutch oven, brown the sausage over medium heat, breaking it up with a spoon. Drain off any excess grease.

Add the diced onion and minced garlic to the pot and cook until softened, about 5 minutes.

Pour in the chicken broth and bring to a boil. Add the chopped kale and cannellini beans. Reduce heat and simmer for 15-20 minutes, or until the kale is tender.

Stir in the red pepper flakes, salt, and pepper to taste.

Serve hot, garnished with grated Parmesan cheese.