"I really felt a responsibility to try to find the best eight doughnuts to send out to my fellow Canadians," Priestley said Tuesday.
"Tim Hortons is part of my country, and I get very defensive of Tim Hortons, and I feel like I need to protect the menu here, so I'll do everything I can to make sure nothing untoward is going to happen to my Tim Hortons menu."
Priestley was among four judges who chose eight finalists in the "Duelling Donuts" contest, which asked Canadians to submit their ideas for a new doughnut. The chain received some 63,000 entries.
The panel, which was given 16 doughnuts to try, eschewed some of the more far-out combinations — ingredients included devil's food cake, pretzels, caramel popcorn and chunky peach filling — for the simpler, more elegant pastries.
Among the finalists chosen were the melty-marshmallow "S'more Of It," the banana-cream "Monkey C-Donut, Monkey Do-Nut," the self-explanatory "Dark Chocolate Cherry Chunk" and the "Oreo Borealis."
The recreation of Nabisco's classic cream-filled cookie earned top honours from the panel, which also featured execs from Tim Hortons (TSX:THI) and TV host Ben Mulroney.
The contest was dreamed up after Priestley appeared in an episode of the sitcom "How I Met Your Mother" last February, which riffed on the idea that Canadians were defined by their double-doubles and Dutchies. In a fake documentary, the Los Angeles-based actor claimed he had invented "The Priestley," a strawberry-vanilla doughnut with a chocolate Timbit nestled inside.
Tim Hortons then created a batch of the fictional pastry, and asked Canada to bring their own doughnut dreams to life.
"The reason that bit on 'How I Met Your Mother' was so funny is because it's true," said Priestley. "We are a nation of doughnut-eating people. ... It's so random and strange but that's just part of who we are. And we are also a nation of people who aren't afraid to laugh at ourselves, and that's where this stems from."
Priestley, who rose to fame for his role as squeaky-clean teen Brandon Walsh on "Beverly Hills, 90210" and currently stars in TV's "Call Me Fitz," took his role in the judging process very seriously.
Over the course of Tuesday's tasting event, he and his fellow panellists dropped culinary know-how in discussing flavour profiles, the balance of potential versus execution, the grammatical precision of each user-written doughnut description, and the target market, asking whether or not "a hockey dad at 5 a.m." would want to order certain entries.
"I have always been a great flag-waving Canadian, even though I've lived in America for the greater part of my life now," said the 43-year-old. "Tim Hortons has been a part of my entire life here in Canada, and for a lot of us, certainly from my generation going back, I think there are some of us who have not known a Canada without Tim Hortons. It's just a part of the fabric of our country."
And speaking of fabric — now that he's done sampling Canadians' wildest baked fantasies, Priestley is focused on getting that blazer to fit again.
"Maybe I'll just jog to the airport from here, maybe go for a cleanse for the next three or four days."
The contest winner will receive a $10,000 grand prize. A Tim Hortons spokeswoman says "the expectation" is the winning doughnut will also replicated in stores nationwide.
Canadians can vote online on the last eight doughnuts standing beginning Aug. 5.
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