IN HER 40 YEARS at Frankford High School, culinary-arts teacher Wilma Stephenson has taught hundreds of students that "a dream is a reality that hasn't come true yet." It's her mantra - her recipe for success.

And with it she has inspired these teens to work hard in life - and in the kitchen - to be the best chefs and the best people they can be. Stephenson's story is the basis for "Pressure Cooker," which opens today at the Ritz at the Bourse.

Jennifer Grausman and Mark Becker's 2007 documentary, which won top prize at Philadelphia CineFest earlier this year, follows the demanding yet charming Stephenson and her culinary-arts class.

Stephenson, who began the culinary-arts program in 1999, has helped her students rake in more than $3 million in scholarship money from the national Careers in Culinary Arts cooking competition held each March.

The documentary doesn't just follow the students prepping for the competition. It explores their dreams of getting out of Frankford High, where metal detectors are as commonplace as chalkboards, and more than 40 percent of students drop out before their senior year.

Stephenson knows what she and her kids are up against - and it shows through her unforgiving teaching style.

"I do not give them a break in any way, shape or form," she said in an interview with the Daily News last week. "And I believe if they can survive my class they can survive life."

In a given school year, Stephenson might start with 180 students, but within a week about 45 will drop out.

There's no cutting corners (watch the students tirelessly carve potatoes and meticulously arrange crepes) and the class rules are law.

If you're late one time, you're out. If you chew gum one time, you're out. No long fingernails, no big earrings, no pocketbooks, bookbags, coats, hoodies or bulky clothing. All students must wear the school uniform, a chef jacket and have all hair covered and hands washed before class begins.

There's something captivating about Stephenson's intensity and something heartwarming about her tough-as-nails teaching style. Her crankiness can be forgiven because of how hard she's rooting for each student.

The students' stories are equally riveting.

Erica Gaither balances caring for her blind and developmentally disabled sister with constant cooking practice for the competition.

Tyree Dudley navigates the football field and the kitchen with a competitive eagerness and charm. His dream is to someday open up a restaurant with his friends.

Fatoumata Dembele, a native of Africa, had been in the U.S. for less than four years when she walked into Stephenson's culinary boot camp.

Today Dembele will attend the movie's premiere at the Ritz Bourse rather than attend her own high school graduation. Stephenson and most of the class will be there, too.

The classroom as family that developed amid the rattling of pots and pans was an angle co-creator Grausman hadn't foreseen. But it became the documentary's most dominant theme.

"We always had our overarching structure but what was interesting was this surrogate family that was built in the kitchen with Stephenson and the kids," Grausman said. "They became really, really close and that story line wound up interesting us even more."

Grausman and the camera crew faced obstacles of their own - in the nine months they were filming, Stephenson kicked them out of her kitchen at least three times.

"Early on I treated them horrible," Stephenson said. "I was so mean to them. Anybody in their right mind would have left the first day."

But Grausman, a newbie documentarian, said she didn't know any better and remained determined to make her film.

"Her [Stephenson's] love for them was palpable," she said. "I felt there was something special going on in this classroom and I knew I had to capture that." *