Meg Cabot doesn’t often travel long distances for onion sandwiches.

The author of more than 50 young adult and adult novels — including the wildly popular “Princess Diaries” which was adapted for the silver screen — Cabot has sold more than 15 million copies of her books worldwide.

But in mid-July, Cabot will be pulling up the stakes at her Key West home to make a temporary three-day home in Minnesota.

And all for the intrigue of onion sandwiches.

“I’ve never actually had one,” admits the 40-something Indiana native. “But they’re a big draw.”

As readers of the Betsy-Tacy novels will know, onion sandwiches are just one of several abiding symbols of small-town charm and simple pleasure found in Maud Hart Lovelace’s most enduring stories. And onion sandwiches will be a signature fare during the 2009 Betsy-Tacy Convention to be held July 17-20 at the Alltel Center in Mankato.

Cabot said she received an e-mail about the convention a couple of years ago. Having read the Betsy-Tacy novels for the first time as a 30-year-old, the 40-something Cabot said she fell in love instantly with their quirky characters and timeless relevance.

So, naturally, she accepted immediately the invitation to speak in Mankato during the convention provided one thing: She would have the chance to taste an onion sandwich.

“(Lovelace’s) books have a certain quality that is appealing even today,” said Cabot, who is hosting a public talk and book signing in Mankato on July 20. “The characters and the stories are still so relevant to today’s teens.”

And relevant, too, to the throngs of Betsy-Tacy fans who are planning to converge on the original Deep Valley for the convention.

Barb Fecteau lives in Beverly, Mass., and is a librarian and lifelong fan of the Betsy-Tacy novels. She’s also part of an organization called the Forget-Me-Nots, which is a nationwide Lovelace fan club that is coordinating the convention (the local Betsy-Tacy Society is helping with tours and hospitality).

Fecteau said members of the Forget-Me-Nots hail from every corner of the country. Many of them, she said, have been to Mankato before. In fact, Fecteau has traveled to Mankato three times and knows the layout so well she is leading one of the tour buses around town.

During the convention, festivities will include turn-of-the-century attire (including parade), picnics, dinners, vendors, games speakers and plenty of tours. The Amboy Community Theater also will be performing scenes from Betsy’s wedding.

“If we’ve done our job correctly,” Fecteau said, “it will look Mankato circa 1910 for the weekend.”