Last year, when owner/chef Nelson Perkins revealed plans to open Colt & Gray, he swore up and down that, if nothing else, his kitchen would put forth Denver's best burger. In a city that lives and dies by its beef, those were fighting words. And when that city is suddenly enjoying a windfall of burger joints — with more in the pipeline — that kind of declaration holds as much water as a leaky thimble. But you know what? Perkins was the wrong guy to doubt, because his burger — a stocky, juice-drooling hand-formed patty of loosely packed, house-ground dry-aged chuck, paved, if you want, with a swatch of really good Gruyère and shoved between the lightly grilled cheeks of a brioche bun — is indeed the best burger in town.