The bacon-maple doughnut either represents the beginnings or the highwater mark of the bacon craze, now currently in its backlash phase. A few years before we were ovewhelmed by Bacon Salts, bacon bandages, and bacon caramels, Portland’s Voodoo Doughnuts introduced a bacon-maple bar that Anthony Bourdain made nationally famous. Soon after, everyone wanted bacon for dessert.I found Voodoo a grim, grotty little place with mediocre doughnuts and a great shtick, so I approached the smoky maple bacon bar at Frost, a doughnut shop in Mill Creek with suspicion tinged, even, with hostility. They won me over.The three-month-old Frost’s doughnuts range from the classic to the baroque, with daily specials announced via Twitter and Facebook. A half-hour spent with a plastic knife and a dozen doughnuts — that is to say, roughly half of the day’s offerings — left me with a progressive case of the sugar shakes and the impression of varying levels of quality. Staying simple appears to pay off: The glazed raised and French crullers were impeccable, while the most over-the-top, the red velvet with a pouf of cream-cheese frosting in the center, proved disgusting. The straightforward cake doughnuts with elaborate frostings — Mexican chocolate, white chocolate and raspberry, salted caramel — came out fine, if dry.Perhaps the two best doughnuts of the dozen this dedicated taster consumed were the bourbon caramel pecan — they could have smeared that goo on three-year-old snow tires and it would have tasted great — and the maple bacon bar. It wasn’t so much the crunchy meat, it was the nostalgia that propelled the doughnut into the top ranks, the impression each bite gave of a Sunday-morning trip to the diner, the familiar but infrequent pleasure of a short stack and a few strips of bacon drenched in warm syrup.While Frost’s consistency isn’t yet there, the shop’s boundless attempts to reinvent the doughnut — and daily — make it worth an occasional 25-minute expedition from central Seattle. The owners are rumored to be scouting a second location closer to us, and the store design and branding-intense paraphernalia seem to suggest an empire in the making. Are doughnuts the next cupcakes? Perhaps.