Marla Rubin is sitting in a Covent Garden cafe with a big mug of hot chocolate and an even bigger dose of jet lag.

A series of remarkable milestones have led the Canadian-born theatre producer to this moment of calm. The most recent was in New York when she and her stellar cast of Samuel L Jackson and Angela Bassett celebrated the opening night of The Mountaintop on Broadway. Another was in 2009, at the show's first night at Theatre 503 - a venue above a south London pub. During the curtain call Rubin wondered if the play was as "amazing" as she thought it was. She went to the after-show party, met the play's little-known American writer, Katori Hall, and set in motion its transfer to the West End.

A few months later, along came the proof of The Mountaintop's heft. It beat runaway favourites Jerusalem and Enron to win the Olivier Award for best new play. For Rubin, this was perhaps the greatest milestone of them all - especially after having come away empty-handed when her first play, Festen, was nominated for a record five Oliviers five years earlier.

She will never forget the night she won. "I sat there in utter disbelief. All I could think was: 'That's a very strange way to pronounce Jerusalem'," she says.

Rubin, who exudes a buzzy energy that manages to be both convivial and business-like, has forged a reputation as a producer of powerful new work for the stage. This is rare enough in an industry where the straight play represents the highest risk for West End and Broadway producers. Musicals - preferably boasting a famous band's back-catalogue - are the surer bet.

This is why most commercial theatre producers would not look twice at a hard-hitting drama about a dysfunctional family, or a talky two-hander about Martin Luther King set during the night before his assassination - the subjects of Festen and The Mountaintop respectively. But then Rubin is not like most commercial producers. For it is not just old-fashioned acumen that she uses to decide which play she is going to sink her and other people's money into. She also uses a slightly less conventional method - the Jewish guide to decision-making that is known as tikkun olam.

"It means to repair or heal the world", says Rubin about the tradition that has Talmudic roots. "And that's what I try to achieve with the plays I put on and the stories they tell. Ultimately, what I'm passionate about is in speaking truth to power, and in portraying socially relevant stories in which the underdog wins. That is celebrating characters who have the guts - despite their very real fear and pain - to stand up to their abusers and come out empowered ."

It is that challenge that forms the core of the work produced by Rubin. In Festen, which started life as a film made by the Danish collective, Dogme, an adult son challenges an abusive patriarch. The challenge in The Mountaintop is represented by Martin Luther King who battled against the civil wrongs inflicted on an entire people. And the challenge contained in Rubin's next show promises to be almost as daunting. "I'm going to take on the subject of school bullying," she says, with more than a hint of steel. "I'm going to produce the stage version of Let the Right One In."

For cinema-goers the prospect of the cult Swedish film, in which a bullied schoolboy befriends a girl vampire, being given a life on stage is intriguing. For theatre-goers, the fact that the production will be directed by John Tiffany, director of Black Watch, is very exciting indeed.

"Let the Right One In has exactly the kind of story I look for," continues Rubin. "The kind that has the potential to empower members of the audience. I still receive letters from all over the world from people who have seen Festen. They say the play has given them the courage to face their own childhood traumas, whatever they may have been. And there is nothing more rewarding than that."

Beneath Rubin's Canadian accent it is sometimes possible to detect a tremor of emotion that reveals just how deeply she feels about the themes of the work she produces. Sometimes they are very close to her heart. Bullying was something that she encountered as a schoolgirl in Montreal. There was a boy who made her life so miserable that she eventually had to change schools. So there is a kind of karma in doing a play on the subject. And karma is present in Rubin's spiritual life, too.

"I'm a Jew-Bu," she says breezily. "I'm a Jewish Buddhist. About half and half."

The Buddhist half evolved after Rubin left Montreal where she was born and raised by a family that was atheist on her father's side and observant on her mother's. After graduating from Columbia University in New York, she was awarded a cross-cultural fellowship to Japan and moved to Tokyo.

"It was in Japan where I became aware that it was possible to integrate Buddhist practice into everyday life. It is a religion that does not judge. And I had long ago come to the view that, while Judaism provides a deeply sustaining ethical heritage, it can also be tremendously critical." And as she has got older, she has also found it difficult to accept Orthodox attitudes towards women.

After Tokyo came Los Angeles, and a move first into documentaries and then reality TV (the latter "when it was socially conscious, before it became the exploitative, social-Darwinist nightmare that it is today").

She then turned to fiction and began working with young writers on film scripts. To her bemusement, she sold several feature projects to the studios and was rewarded handsomely for it. The movies however languished in the dreaded Hollywood state known as "development hell", a thoroughly frustrating experience for her.

So she moved to London, where she still lives, and launched her theatre career by persuading Dogme director, Thomas Vinterberg, to sell the theatrical rights to Festen.

Since the play premiered at London's Almeida theatre in 2004, it has been performed all over the world. For Rubin its success has proved to her that in life it is important to be more curious than afraid.

"Theatre is a sacred space where higher truths can be experienced on a visceral level, free from the noise of the self-absorbed, materialist rat race outside its doors," she says. "In that sense it provides healing of the highest form, which is tikkun olam at its core."