Well, if we’re going to nominate what we individually believe is the best, let me put any place that can compete with my own homemade burger:)
I use Whole Foods’ 1/4lb of grassfed 85/15 or Springfield Butcher’s ground chuck with no spices beyond a little salt and then grill it over a medium-hot natural charcoal fire (not started with fluid) to just the other side of medium. I flame toast a fresh-baked Brioche bun or even a Wonder bun, I don’t care, because the burger is the centerpiece.
Top it with a slice of a homegrown tomato, one piece of Romaine lettuce (NOT shredded), and very little mayo and that’s it. I’ll add cheese only half the time and then only enough to ensure it enhances and doesn’t overpower the burger. More often, I’ll skip the lettuce and tomato and dress with slaw (made according to my NC Grandmother’s recipe which includes yellow mustard) and maybe a little chili.
There are places I’ve been which equal or beat mine. One is at the restaurant at the Biltmore House in Asheville, NC. They use their raised on-site Angus and it’s amazing.