Remove casing from sausage and crumble into a large pot.
Add chopped onion, and cook over medium heat.
When sausage is almost done, add garlic and continue cooking 1 minute.
Add broth, potatoes. Boil until potato is cooked. Stir in beans.
Add spinach. Continue boiling until spinach is lightly wilted.
Remove soup from heat, stir in evaporated milk, and season to taste.
Top with Parmesan cheese and serve hot.