Louis Lunch is a Yale tradition dating back to 1895.   Some say they may have invented the hamburger.

The burger is worthy of its history.  Loose packed ground beef broiled a perfect medium rare, a slice of grilled onion, a slice of tomato, and slathers of melted cheddar on both pieces of toasted bread.

The broilers are ancient.  And unique.  The burgers go between wire griddles, slice into the broiler and broil vertically.