In a 5 to 6 quart pan over medium-high heat, melt butter with olive oil. Add onions and stir often until they're limp and liquid has evaporated, about 8-10 minutes. Add wine; stir occasionally until liquid has evaporated and onions are sweet to taste and very tender, about 30 minutes. Add salt to taste, if desired.
While onions are cooking, prepare bacon.
Portion ground beef into 4 patties, season with salt and pepper, garlic, onion powder and Worcestershire.Grill to desired doneness.
Top each patty with brie slice, and cover until cheese melts. Top with crispy bacon, and caramelized onions.