It's late, I've shared a bottle of old vines tempernillo and havent taken time read thru the 7 pages of postings - but just in case anyone missed mentioning Flagg's Bistro on Alma btw broadwy and 10th. Interesting story/guy, he bakes his own buns, a bit "dirty" but such a good burger! I've tried all the others (i read) mentioned as when i first moved here I had a bit of time on my hands and decided that this was my project to find the best burger. I seem to remember that at the time red onion came in at the top, but flagg's beats it and any others.