Heat olive oil in a large skillet over medium-high heat.
Once hot, add sliced chicken sausage, and brown lightly on both sides to bring out the great flavor, stirring frequently, about 3-4 minutes.
Place chicken sausage, garlic, onion, carrots, celery, beans, oregano, parsley and bay leaves into a 6-qt slow cooker/crock pot. Stir in chicken broth and 2 cups water until well combined; season with salt and pepper, to taste.
Cover and cook on low heat for 6-7 hours or high heat for 3-4 hours. Stir in spinach until just wilted.
Serve hot and top each serving with Parmesan cheese.