CHAPEL HILL, N.C.  After generations of being smothered by a blanket of marshmallows on Thanksgiving and then forgotten for another 11 months, the irrepressible sweet potato is having its moment.

American farmers expect to harvest a record two billion pounds this year, almost half of that here in the nation’s most prolific sweet potato state. Sweet potatoes have achieved a status that just a few years ago would have seemed laughable.

They may even be hip.

Like skinny jeans, bamboo-frame bicycles or Disney stars, what is in and what is out can change in a flash. Just three years ago, The Wall Street Journal expressed the food world’s consensus view and declared on its front page that after the Thanksgiving dishes were cleared, the sweet potato was no more special than a turnip.

Yet the rough-skinned vegetable is arriving these days on plates both elevated and humble, from fancy state meals made with produce from the White House organic garden to a seasonal side dish served with cinnamon dipping sauce at White Castle. Europeans, too, have begun romancing the American-grown sweet potato, and the sweet potato fry is getting so popular that research has shown almost half the children in America under 12 have tried one.