One California school district is taking an innovative approach to address the numerous student complaints about the quality of its lunch program.

The Santa Clarita Valley school systems in California lost $250,000 in cafeteria sales last year when students rejected healthier fare designed to meet new federal nutrition standards. Now the districts are trying to win back diners by hiring a chef trained at Le Cordon Bleu, the prestigious culinary school.

To make the lower-fat, reduced-sodium fare more appealing, new hire Brittany Young is employing restaurant-style techniques. She moved popcorn chicken out of a steamy wax bag and into an open boat serving platter. She told kitchen staff to wipe down serving bowls so chow mein noodles don’t hang over the side. “Think about how [you’d] like to see the food,” Ms. Young told them.

Ms. Young plans to add a new item to the school menu in January, a chicken quesadilla that scored high marks with student taste testers.

School cafeterias, long run by no-frills lunch ladies, are turning to fancier chefs and culinary-school graduates to improve their food. While some districts have employed professionally trained cooks for years, the introduction of tougher nutrition rules in 2012 is making them more of a necessity as students shun wholesome dishes and cafeteria revenues fall, schools say.

“Once you move from chicken nuggets to roast chicken, somebody needs to know how to cook,” said Ann Cooper, director of food services for the Boulder Valley School District in Colorado. The number of districts employing professionally trained cooks has “gone from virtually none to dozens, if not hundreds, in a decade.”