Slow Cooker Creamy Tortellini Soup

Italian sausage, browned (you can also do ½ ground beef and ½ sausage)

jar marinara sauce

chicken broth

pkg regular cream cheese, cut into 1 inch chunks

pkg sliced fresh mushrooms

bag (4.5 oz) fresh spinach leaves

(16-19 oz) pkg frozen cheese tortellini

shredded parmesan cheese, optional for topping