Elicia Mackenzie Bounces toward me to say hello as if propelled by an alpine gust. The star of The Sound of Music, an $11-million show put on by Toronto’s pre-eminent theatre keener, David Mirvish, is a petite parcel of youthful exuberance, whiskers-on-kittens cute. She’s wearing a pair of leggings the shade of Welch’s grape juice and a cozy parka, her glossy bob kept tidy with a plastic hair band she could well have borrowed from Gretl von Trapp; she’s 23 (going on 24) and improbably fresh—the word “fresh” seems stale compared to what she is. We meet on a rare day off, but even out of character, she seems custom-made for mountaintop twirling and pinafore wearing. It’s not hard to see why she has become Toronto’s latest stage darling, receiving (and deserving) much of the credit for The Sound of Music’s staggering success.

While musical theatre wheezes its way through the recession in the U.S., audiences have been yodel-ay-hee-hoo-ing in and out of the Princess of Wales theatre since the show opened last October. Over the Christmas holidays, ticket sales of $3.5 million broke all Mirvish box office records. Even the critics, who relish pooh-poohing such commercially successful mega-musicals as Dirty Dancing and We Will Rock You, have embraced SOM and its effervescent leading lady. The National Post’s critic Robert Cushman was direct in his assessment: “The hills are alive, and it’s very impressive. So is she.”

The role of Maria is MacKenzie’s first professional gig, and she is among the youngest performers ever to take it on. (Mary Martin was 45 when she starred in the Rodgers and Hammerstein musical’s 1959 Broadway debut; Julie Andrews, the most beloved and iconic of all Marias, was 29 when the film was released in 1965.) The part is widely considered the most challenging in musical theatre: it demands a great deal of vocal agility and stamina (Maria is onstage for nearly every scene), as well as the ability to reconcile a collection of contradictions. She must seem both innocent and seductive, pious and defiant, tomboyish and feminine, maternal and childlike. And because Andrews owns the role in our collective imagination, any new Maria is bound to suffer comparisons. On top of all that, MacKenzie won the role on CBC’s televised casting call How Do You Solve a Problem Like Maria? (reality TV, even reality TV conceived by Sir Andrew Lloyd Webber, isn’t exactly a respected medium in most theatre circles).

Judges on the seven-week TV show—which earned some of the highest ratings in CBC history—auditioned more than 2,000 would-be singing nuns. MacKenzie went virtually unnoticed until she donned top hat and sequined vest and belted out “Cabaret” with all the fearless, gut-spilling sass of a prettier, pocket-sized Liza Minnelli, proving that her range is more formidable than, well, any mountain’s. She never thought she’d win, though: “I knew that I had done my best, and that’s always nice, but it was crazy to hear my name. Like, wait a second! You can’t be serious!”

Raised in Surrey, B.C., she grew up singing in children’s choirs and entering junior talent competitions. After high school, she took a job performing as a pioneer at the Capilano Suspension Bridge, a local theme park, and attended Capilano College to study musical theatre. When her uncle noticed an ad for CBC’s Maria auditions in the Penticton Herald, MacKenzie opted to go even though she’d just won a role as one of Cinderella’s wicked stepsisters (now there’s a stretch) at the Vancouver East Cultural Centre. Taking a leap of faith, she traded the sure thing for a shot at something bigger.

Like anyone else with a pulse, Mac­Kenzie knew a lot of the musical’s numbers—a plus since she had just 10 weeks between talent show triumph and opening night. The warp speed orientation was an unexpected blessing. Her lack of training and artifice do much to rescue the show from cavity-inducing schlock; the production rests largely on her five-foot-three frame and becomes as likeable and believable as she is. In the depressed economy, audiences aren’t craving anything too gritty or avant-garde. The Sound of Music—with its consoling familiarity and retro optimism—is the entertainment equivalent of hot chocolate, or warm woollen mittens. “I always want the audience to leave happy: that’s one of my goals,” MacKenzie says.

Just as Maria leaves the convent to meet a bigger, bewildering world, MacKenzie left her parents’ place in Surrey to greet her share of scary unknowns: she had never lived on her own or even visited Toronto before coming here for Maria school. Her observations of her adopted city: “It smells!” she says with a giggle, crinkling her tiny nose. Then, in her wide-eyed way, she turns to the positive: “But there are a lot of opportunities here.” She’s still getting to know her new town and misses family, friends and the dog she left behind in the old one. She’s living in a condo just blocks from the Princess of Wales, and when she’s not at the theatre (where she spends about 25 hours a week), she likes to shop at Whole Foods and tries to catch movies and plays as often as possible.

Looking into the future, she has her heart set on Broadway; the role of Elphaba in Wicked is a particular dream: “It’s about finding the power within yourself. That’s a good message.” True, you can’t quite see her taking on some of musical theatre’s edgier roles (Elicia as Rent’s smack-addicted cage dancer, probably not), but as far as homespun heroines go, she may be the sweetest find since crisp apple strudel.