New York singer/songwriter Nellie McKay is absolutely brilliant and bloody confounding.

She has more retro range than Amy Winehouse, more musical depth than Alicia Keys and more sexy charisma than Rihanna. And she may be more talented than all three combined. Seriously.

However, trying to explain McKay, 25, to the uninitiated is not easy. She is to music what "Project Runway" winner Christian Siriano is to fashion: fierce, funny, full of herself and over-the-top gifted beyond her years.

Like Rufus Wainwright, McKay (rhymes with McShy) is an ambitious, idiosyncratic musicmaker who creates a smart/smart-alecky and intoxicating mix of Broadway, cabaret, jazz, hip-hop and humor. She's appeared in both Bertolt Brecht's "A Threepenny Opera" and Garrison Keillor's "A Prairie Home Companion." Her music owes as much to Doris Day as to Eminem.

Trying to interview McKay, who opens a three-night stand Sunday at the Dakota Jazz Club, is a cat-and-mouse game.

"Interviews should be vague," she said from Los Angeles. During a 45-minute conversation as she drove to get her computer fixed, she fell into character, talking with a slow, almost drawling tone like vaudevillian crooner Leon Redbone.

I asked her to choose 10 adjectives that described her in addition to "vague." Her response: "Vaguer. Vague-est. V8-full. Vigorous. Vapid. Vacuous. Vengeful. Violet-colored. Vile. Vicious."

Very cute if a bit vaporous.

Amused but still confused, I contacted people who have worked with McKay to shed some light. Minneapolis singer/songwriter Adam Levy (of Honeydogs fame) toured with her for three nights last year as part of Aimee Mann's Christmas show.

"She's a total oddball, but everybody that's around her falls in love with her -- girls and boys," he said. "She's just a joy to be around. She's super well-read. Some people think it might be an act but there's a kind of naiveté about her. Like, she wouldn't let on that she knew certain things that happened after 1960 in terms of music. Her music sounds like it's from another era, but she knows what's up."

McKay was featured in January on "PHC," and she'll join Keillor again next weekend when his show travels to New York City. The man of letters was eloquent and effusive in his praise.

"Nellie is very well put together, very cool, big hair, dressed up like a 1948 babe, a real actress, which you can tell from the perfect diction," Keillor said via e-mail. "Her stuff is hip and funny, but what got the ['Prairie Home'] audience was her rendition of an old love song, 'If I Had You,' and the lines about climbing a snow-capped mountain and crossing the burning desert, which she did with sweet dedication. She's a torch singer posing as a downtown songwriter."

Double trouble

It was obvious that McKay was a handful when she recorded her debut disc in 2004. She wanted the project, produced by Beatles engineer Geoff Emerick, to be a double album. Columbia Records preferred a single disc. McKay prevailed but only after agreeing to finance the additional recording herself.

Columbia rejected such proposed titles as "Penis Envy" before settling on "Get Away From Me," a jab at Norah Jones' blockbuster "Come Away With Me." The 18 songs were a double espresso compared with Norah's mocha latte, reflecting McKay's eclectic tastes, biting humor and lefty, pro-PETA politics. When she made her Minneapolis debut at the Fine Line Music Cafe in March 2004, the show was like one "Saturday Night Live" musical sketch after another, peppered with enough musical sophistication on the piano to warrant taking her seriously.

McKay and Columbia again bumped heads over her second album, which featured duets with k.d. lang and Cyndi Lauper. She wanted to include 23 songs (65 minutes of music); the label insisted on 16. The disc was repeatedly delayed until Columbia dropped McKay, and she released "Pretty Little Head" on her own.

Last year, McKay reined herself in on "Obligatory Villagers" -- a mere nine songs lasting 31 minutes, covering rap, reggae, disco and her brand of jazz, featuring saxophone great Phil Woods and singer Bob Dorough (of "Schoolhouse Rock" renown). Of course, her lyrics are still razor-sharp, as evidenced on "Mother of Pearl," which is to feminism what Randy Newman's hit "Short People" is to the vertically impaired.

London-born, Harlem-bred

McKay was born in London on April 13, 1982, to an American actress, Robin Pappas, and a Scottish writer/director, Malcolm McKay. After the couple divorced in 1984, mother and daughter moved to New York.

McKay "was just brilliant as a kid, eclectic and very precocious," said Minneapolis teacher and musician Peter Lawton, who lived in Pappas' Harlem home for four years during college; Nellie was 6 when they met. "She had a wicked sense of humor and a sense of irony as a little one. She had personas that she would put on at the dinner table and for parties."

Al Jolson, Tin Pan Alley and British music-hall tunes dominated the record player, he recalled: "She has a sensibility that's much older." And she got involved in her mom's political issues. "Nellie read the literature and could spout off on it."

In 1994, Pappas and McKay headed to Olympia, Wash., for a year before relocating to Pennsylvania's Pocono Mountains. In addition to playing piano in her high school jazz band, the prodigious teen fell in with a crowd of jazz pros, including sax star Woods, with whom she studied arranging. After attending Manhattan School of Music for two years, she dropped out to do standup comedy in New York clubs, then sang in the anti-folk music scene.

Over the years, she has amassed a vast knowledge of popular music and quite a collection of old vinyl. When asked to talk about her trove of tunes, she simply says: "It's very dusty."

She's obviously aware of contemporary music, as well. How much hip-hop does she listen to?

"It makes up about 13.7 percent of my listening repertoire," she said.

She also listens to "dead people and bands with fruit in the title -- the Fruit Loops, the Orange Peels and the Banana Splits." When I promised to search for downloads of those groups, she laughed. "Maybe you want to spare yourself."

Stepping out of character

Even though her songs are highly literate, McKay was a woman of few words on the phone. However, she did step out of character twice -- both times to jump on her soapbox and speak at articulate length.

The first came as she discussed performing in "Threepenny Opera" with Lauper in 2006. While she enjoyed the work and making friends with ushers and guards (she still goes drinking with them), she was displeased by how the political message of the show was downplayed and she was put off by overpriced tickets and the sale of perfumes in the theater lobby.

Her other harangue was about Columbia University's plans to demolish 18 acres -- including historic buildings not far from her childhood home -- for a biotech research center.

Will she get political in Minneapolis? Will she perform "Sari" (pronounced "sorry"), a 2004 rap tune in which she rants about things that irritate her -- including herself -- and namechecks the late Sen. Paul Wellstone?

"Do you think I should?" she asked.

She did promise to have her old pal Lawton as opening act. On Sunday, the Minneapolis singer/guitarist will team up with Craig Wright -- now a Hollywood screenwriter known for "Six Feet Under" and "Dirty Sexy Money" -- to revive their 1990s Twin Cities duo the Tropicals. Then on Monday and Tuesday, Lawton will take over as lead singer in his current combo, Kangaroo.

Over the years, Lawton has kept in touch with McKay's mother and admired the singer/songwriter from afar.

"I'm in disbelief," he said last week. "I picture this 9-year-old girl, so it's hard to put this grown-up woman together with the girl. But it all makes sense. In her music, there's not one voice; there's a collection of voices, which, I think, is part of the charm -- that she can do them all so well. She's got talent to spare. When I saw her at the Fine Line, it was just doe-eyed twentysomething girls everywhere -- just like they were looking up at Barack Obama or someone."

Jon Bream • 612-673-1719