Wilma Stephenson runs her high-school culinary-arts class like a Marine sergeant: She’s loud, cranky, and prone to threatening bodily harm. Stephenson, a central figure in co-directors Jennifer Grausman and Mark Becker’s likable, straightforward Pressure Cooker, is a slacker’s nightmare and a nerd’s masochistic dream. For her students at a northeastern Philadelphia school, she might also be their ticket out of stifling homes and a dead-end neighborhood. Pressure Cooker focuses on three seniors taking Stephenson’s class to prepare for the Culinary Institute of America’s scholarship competition: Fatoumata, a recent immigrant from Africa who longs to escape her oppressive father; Tyree, a football player hoping to secure a future not only for himself but for his single mom; and Erica, a young woman who after a lifetime of caring for her blind sister has decided to get hers. The intersection of food and identity is briefly explored, and the prep/exam sequences have a tension and charm that keep the film moving toward its literally rewarding climax. Stephenson looms largest as a reminder of what the right teacher can mean to a kid looking for a way out; it takes a strong woman and a special grace not only to let her protégés go, year after year, but to practically shove them out the door.