Brown bacon, rough chop and set bacon aside. Add the bacon grease to the pot you're going to make your soup in

Add butter/margarine and let it melt. Add the all purpose flour and stir til smooth

Add chicken broth and milk. Bring to boil

While it's coming to a boil, half cook the onion ( I dice my onion so it cooks quickly)

When base is boiling, add the onions, potatoes, bacon (and mushrooms if you choose to)

Reduce heat to low and simmer for at least an hour or until potatoes are soft, stirring occasionally