Sweet Potato & Sausage soup

1 T. olive oil
1 large yellow onion, diced
2 cloves garlic, minced
salt & pepper
3/4 lb Italian sausage, casings removed
2 sweet potatoes, peeled and diced, medium
4 C. chicken broth
3/4 C. small pasta shells
4 C. roughly chopped kale or Swiss chard
grated Parmesan cheese

In a large pot, over medium heat, add onion and garlic, about 6 minutes.  Season with salt & pepper.  Add sausage and cook until browned.  Add sweet potatoes, broth and 2 cups water and bring to a boil.  Add pasta and cook 3 minutes less than package directions.  Reduce and simmer, add greens and cook another 4 minutes.  Serve with Parmesan cheese.