Mary Stuart Masterson on the set of The Cake Eaters, premiering this weekend at the Tribeca Film Festival (Photos: The 7th Floor/57th and Irving)

Really, for Mary Stuart Masterson, it came out of nowhere. Not that she didn't want it; the veteran actress had her own scripts circulating in Hollywood in various stages of development -- as many as three, by her own count. In 2001, she had adapted and directed a half-hour segment for a Showtime sci-fi anthology (the other directors: Helen Mirren and Anne Heche). It was fun, but it didn't feel right, as though the writer and director in her were battling it out. There was more searching, more waiting, more roles -- a few indies, a lot of TV.

Then came the script. It arrived with financing and a funny name: The Cake Eaters. Very indie, kind of quirky. Sincere. Humane. Masterson had a read-through and that settled it.

She was directing.

Less than two years later, Masterson is preparing The Cake Eaters -- and herself -- for the film's world premiere this weekend in Tribeca. The story of two families and three generations facing emotional new challenges in the wake of a mother's death, a girl's illness and a lost brother's return, The Cake Eaters appealed to Masterson for what she calls "a beating heart and a kind of innocence" -- neither of which were traits she attributed to the contemporary independent film climate in general, but both of which she said she sought to emphasize onscreen and on-set.

"I feel like I've been going to school a long time on this, and have been very, very fortunate to work with so many great people -- great actors, great directors, great writers," she told The Reeler in a recent interview, a few days removed from completing the film's sound mix (The Cake Eaters was unavailable for screening prior to the festival). "And some not so great in all of the above categories. So obviously there's a great deal I draw from all of that. And most importantly, being a director is being a storyteller, and in a way, a general in an army and also everybody's mother. It's somewhere between all these things -- you play all these roles."

So many roles, in fact, that Masterson remained camped behind the camera for her feature directing bow, leaving the ensemble acting to a cast including Bruce Dern, Elizabeth Ashley, Aaron Stanford, Kristin Stewart, Miriam Shor and the film's writer and co-producer, Jayce Bartok. She produced as well, almost by default but hardly by accident, as per usual with films at The Cake Eaters' miniscule budget level. The middle child in a creative family (her father Peter directed Geraldine Page's Oscar-winning performance in The Trip to Bountiful, her mother Carlin Glynn won the 1979 Tony Award for best actress in a musical), Masterson brought her brother Peter aboard as her cinematographer. She deeply invested herself in Bartok's screenplay, working with him to develop and refine the script for nearly 10 months prior to production.

"I think we both bring that perspective as actors in terms of organically grounding the characters," Bartok said. "She really did a great job of making the narrative organic and solid. There were some more quirky, fanciful things, I think, coming more from indies that I had injected into the story that she solidly tempered -- it made the film that much stronger as a well-built narrative and drama. I was leaning a little more toward these absurd flights of fancy that I think she kind of toned down. It was a really intense process. She's really, really thorough, and she throws herself entirely into her work."

Aaron Stanford and Kristin Stewart share a moment in The Cake Eaters

During the shoot upstate, in Columbia and Greene county farming communities along the Hudson River, Masterson guided her cast and crew through a fast production in typically modest indie conditions. "You know what it's like," Dern told me in an interview from the Chatham, Mass., set of his next film. "You have enough money to make the movie, but you're still flying by the seat of your pants; it's got to be a crew or a company where there's no 'I' in 'team.' There's no dressing rooms; Elizabeth Ashley and I changed in the high school gym -- not in the locker room, but in the gym. We had a cloth hanging down, and she was on one side and I was on the other. That was it. It was primitive conditions in that way. But everybody ate well, and everybody was housed, and we got the movie made in the time it was supposed to be made."

Dern engaged a sequence of sports metaphors to emphasize Masterson's approach: She brought her best game, he said, adding that there wasn't a position she couldn't play at an "all-star level." More specifically, though, he credited her with taking advantage of everything her actors brought to their scenes. "There was room to embroider, room to dance," he said. "She never came in and said, 'This is you, this is you, this is you. Just hit the marks and let's shoot it.' She always let the actors' instincts evolve in a scene, and that's of great concern to me, because I don’t see that near as much as I should anymore."

The inclination would likely be to attribute this latitude to Masterson's own background as an actor. You'd be partly right. "I can say this group of actors was very receptive, very trusting and very grateful for that," she said. "I think because I hadn't directed before in ways that anybody had seen, I had to let people know that I was in command of the material and the set and the production and that they were safe. When it comes to the actual technique of acting roles, I trust everybody to do their jobs. I'm not there to tell them how to do it, and I don't think I could credibly do that."

But she was also quick to note that she didn't treat the job as an "acting promotion" -- that that commonly held perception of actors/directors would be a misunderstanding of her own motives. Dern, who has worked with actor-directors from Jack Nicholson (Drive, He Said) to his ex-wife Diane Ladd (Mrs. Munck) and who will soon make his directing debut in a film starring himself and his daughter Laura, acknowledged the same thing. "She knew that somebody had given her an opportunity to dream her dream," he said. "People had come forward, put their money where their mouths were and let her have that chance. In no way, shape or form was there one second in the time that I was there that she ever abused that privilege. And for that I'll be forever grateful to her; I can say that she's one of maybe two or three people I've worked with in my career who I saw that from."

And as for Tribeca -- a hometown premiere for Masterson, and a short journey into town for much of the cast and crew who worked on the film -- the filmmaker is looking forward to finally sharing The Cake Eaters. "I love film festivals -- especially when you have a movie in a festival," she said. "It's always kind of idealistic; it pushes all those happy art buttons, and you can forget for a minute how damn hard it is to get a film made, and you can enjoy the films and the process and leave the ugly money raising business behind."

She paused. We both knew what was next. "But then there is the selling," she said, a half-laugh alluding to her next stretch of patient anticipation to come. "It's a whole other game, and hopefully we'll be in the position. That'd be great."