Few recent musical comedies generated as much buzz as “The 25th Annual Putnam County Spelling Bee.” Telling the tale of six middle schoolers vying for the county spelling championship, the Tony Award-winning show shattered house records on Broadway, and is now hitting the road.

First stop: San Francisco, and with any luck, audiences here will be as spellbound as the New York throngs. The show is now playing in preview at the Post Theater, with the official opening night set for March 1.

“Putnam County’s” Jewish composer/lyricist William Finn is thrilled about the show’s West Coast premiere .

Finn, 54, was best known for his 1994 musical “Falsettos,” which earned him Tony Awards for best book and best score. But “Putnam County” is his biggest commercial hit to date.

And to think it all started with a call from the late playwright Wendy Wasserstein (“The Heidi Chronicles”), who was one of Finn’s best friends.

“Wendy’s weekend nanny was in an earlier version of the show,” recalls Finn, referring to an extended comedy sketch called “C-R-E-P-U-S-C-L-E,” adding, “She saw it, called me up and said they should make it into a musical.”

That nanny, Sarah Saltzberg, went on to create one of the show’s memorable characters, Logainne Schwartzandgrubenierre.

“I’ve never written a show so quickly,” Finn says. “It just came. We [the show’s creators] were in Barrington, Mass., during a snowy winter. It was an ideal working environment, though I felt a little like Jack Nicholson in ‘The Shining.'”

Like Wasserstein, Finn is one of many of Broadway’s top artists who happen to be Jewish. “Putnam County” sported a nearly all-Jewish creative team including Rebecca Feldman (who conceived the show), Rachel Sheinkin (Tony winner for best book) and director James Lapine.

“It’s a cabal,” jokes Finn. “I guess if there’s a show Jews should be running, it’s this one.”

Though not overtly Jewish, “The 25th Annual Putnam County Spelling Bee” is rife with good humor, much of it reflecting Finn’s twinkly wit. Songs include “I’m Not That Smart,” “My Friend, the Dictionary” and one called “My Unfortunate Erection.”

Finn is enjoying his new celebrity, but he is far from a typical show biz fame junkie. His workweek included teaching a master’s class at NYU’s Graduate Musical Theatre Writing Program, and his previous works, like “Falsettos” and the song cycle “Elegies,” are decidedly esoteric.

He grew up near Boston in a typical Jewish family. His rabbi was esteemed writer Harold Kushner of Temple Israel in Natick, Mass. He graduated from Williams College, where — though an English major — he was awarded the Hutchinson Fellowship in Musical Composition.

His other works include “In Trousers” (winner of the L.A. Drama Critics Award) and “A New Brain” (Lincoln Center/Outer Critics Circle Award winner for best musical). He had talked to Wasserstein about a musical version of her hit play “The Sisters Rosenzweig,” but with her death, that idea remains strictly on the drawing board.

Sustaining his Jewish identity remains an important part of his life. Finn is a long-time member of Beth Simchat Torah, a New York synagogue with predominantly gay and lesbian congregants.

“I love being Jewish,” says Finn. “I’m just a big Jew, and a fat Jew too.”

“The 25th Annual Putnam County Spelling Bee” is now playing 8 p.m. Tuesdays-Saturday, 7 p.m. Sundays, with 2 p.m. weekend matinees. Tickets: $40-$65. Information: (415) 771-6900.