If you want to learn how to make Vietnamese egg rolls, you can always check out a cookbook, a food blog, or perhaps a site like Epicurious.

But Linh Nguyen — who is teaching a cooking class here in San Francisco — says that that's not really the way to do it. In fact, her family doesn't even own a cookbook.

"In a Vietnamese house, there are no measuring spoons or measuring cups," says Nguyen. "Everything is sort of just done by the handful, or the bowlful. And the recipes are all sort of passed down from one person to another."

Nguyen teaches for Culture Kitchen, a company that hires first-generation immigrants as cooking instructors. Unlike Nguyen's family, Culture Kitchen teachers do write down recipes.

But they also focus on that person-to-person tradition — showing how a dish should really taste or look when it's done, and answering all the little questions that come up along the way. Like whether egg rolls are rolled properly.