Stir all ingredients together in a large stockpot, and bring to a boil over high heat, stirring occasionally. Reduce soup to medium-low, and simmer for 10-15 minutes, or until the onions are soft and translucent.
Serve warm, topped with grated Parmesan cheese if desired.
Notes
**I know this “ups” the ingredient total, but if you love garlic, this soup is EXTRA delicious with 2-3 cloves of minced garlic added in. You can just bring them to a boil with the rest of the ingredients.