Since 1936, this family-run counter has defined the Wisconsin butter burger: fresh sirloin on a flat-top, crowned with Wisconsin butter and stewed onions. Named an America’s Classics winner by the James Beard Foundation, it’s repeatedly praised by local food critics and national TV. Expect a living slice of Milwaukee diner culture, tight quarters, and friendly regulars. Go early; the grill hums from breakfast through dinner Tuesday to Saturday. Cashless? No—bring plastic or cash, and a hearty appetite.