Melt the butter (or heat the oil) in a pot over a medium high flame. Add all of the vegetables, and stir occasionally for several minutes until they begin to lightly caramelize on the outside. Add the white wine, and allow to boil off for a minute. Add enough broth to cover by an inch or two, raise the heat until it comes to a boil, and then reduce the heat until it's just high enough to maintain a simmer. Cover and simmer until everything is very tender, ~half an hour. Puree in batches in a food processor or blender (I like a nice smooth puree, but feel free to leave it chunky if you prefer). Return to a pot, add additional broth as needed to get a nice soup consistency, and adjust seasonings to taste.