Cook the bacon separately, then stack and chop.
In a skillet, sauté the onions and mushrooms in the oil. Cook them down well so they are nice and caramelized. Keep the heat on the lower side for this. Let it cook slowly.
While that cooks, put the remaining ingredients into a medium to large soup or stock pot.
When the bacon, mushrooms and onions are ready, add them to the soup and bring everything to a rolling boil. Reduce to a simmer and cook for 5-10 minutes, just to give the flavors a few minutes to really blend together.
Serve and season with salt to taste.
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible.