How top chef Nicole Pisani turned school dinner lady and shook up the whole system

A year ago, Nicole Pisani left her job in a high-end restaurant to become a school cook with a budget of 80p per meal. Sophie Morris finds out what she's learnt – and what the children think of samphire stir-fry and crumbed whitebait

It's half past eleven on a crisp and sunny winter morning and Nicole Pisani is having a carrot mash crisis. In 30 minutes or so, the first of her 600-odd lunch guests will start arriving, but before then, she needs to sort out the carrots and do a tasting of the day's dishes with her kitchen team. Pisani is the chef at Gayhurst Community School, an east London primary that overlooks the highly desirable London Fields, which means the children she feeds leave for school each morning from some of the UK's most in-need postcodes as well as from £1m houses.

Pisani came to Gayhurst a year ago after a career in some of the capital's leading restaurants, latterly Nopi, Ottolenghi's glitzy central London restaurant, where she rose to head chef and cracked out an 80-hour work week. This all changed when she spotted a tweet from Henry Dimbleby, the owner of Leon Restaurants. Dimbleby had recently drawn up the School Food Plan, a set of mandatory standards for food served in maintained and free schools and academies, which came into effect last year. His children were at Gayhurst, and the school needed a new chef. Pisani got the job and set about overhauling the school's menus – with a budget of just 80p per meal – and convincing parents their kids could eat better. In just 12 months, she's set a trend for restaurant chefs moving to schools, and has big plans for a new food-education centre.

Jamie Oliver won our hearts and minds a decade ago with his school-dinners crusade. Can Pisani pick up where he left off? Unfairly, his war on turkey twizzlers was branded a failure because it didn't solve all the problems with school food overnight. Last year, Oliver said his push on school dinners had failed because eating well "is a posh and middle-class concern" and that he hadn't "single-mindedly gone for it".

But there were improvements: economists found that achievement and attendance were up in the schools involved. Thanks to Oliver, school food is back on the agenda, and maybe the gentler approach of Pisani and Dimbleby can shore up its foundations. Already, three other chefs have seen Pisani's example and followed her from stressful kitchens and food businesses into schools, and she has just announced plans for a new dream, her "School of Food", a training centre where school cooks, children and local people can learn about food. "It's the next level for us," she says. "We've made the school dinners work here, the chefs are trained; the last step is to get the kids into the kitchen to understand the food.

"We've just found the space and, if the council says yes, then we'll need to find the money. It won't just be for London schools – hopefully it will work internationally."

First, though, it's Friday and fish day – and fish is notoriously difficult to get children to eat. "In the beginning, the hardest thing for me was getting them to eat fish. You have to give in to certain things, so I gave in to frying fish." It works: one little boy is raring for his fourth portion.

Pisani's fish is shallow-fried hake in a coconut and pumpkin crumb. Since she took over, frozen burgers and pizzas of questionable origin and vegetables boiled until they disintegrate have been replaced with freshly prepared food and a range of flavours as wide as her hungry customers are diverse. Alongside the hake there's a samphire stir-fry with corn, peppers, leeks and kale, the rescued carrot mash mixed with pumpkin, and, controversially, whitebait. The little critters have been cleverly crumbed to obscure their eyes and, amazingly, most children agree to try a few. Ultimately, a quick poll of those eating at the long, low tables laid out in front of the serving station reveals very little love for the whitebait. Nine-year-olds Esme and Georgie say the flavour is a bit too strong for them, but that they'd try them again.

But most have at least tasted the whitebait, one of many small triumphs for Pisani, who this time last year was met with children having meltdowns and parents asking for their children not to be served veg. Pudding is a choice of small strips of chocolate pancake or yoghurt, which brings another surprise: lots of the kids go for the yoghurt. Food costs have gone down (less meat is served and they have a deal on fish through Dimbleby's contacts), but labour costs are up due to increased preparation time. The employees have more responsibility and are more engaged. While this model, as Pisani is busy proving, can be replicated, not every school chef can have a Dimbleby on speed dial.

The smallest children eat first. Pisani has to feed the 600-plus pupils and teachers in an hour, compared with the 550 covers over a full day at Nopi. Staff and sometimes parents eat with the children. Year One teacher Huw Greenwood says the food before was "nice but less exotic", observing that now, the children look forward to lunch. "There's occasionally an unpopular vegetable," he admits, "but there's lots of sharing, which is good."

Trainee teachers Sarah Hutson and India Guthrie are at Gayhurst for five weeks on the School Direct programme. "The food is amazing," Hutson beams. A teaching assistant says she is enjoying the food but, she confides anonymously, "while it's a balanced meal, it's not always to the children's taste."

Communal eating, where the food is acknowledged and discussed, not gobbled down, is at the heart of the School Food Plan, which itself provides some surprises. It isn't a pious, impenetrable vision of daily hummus and lentils and dishes stripped of all sugar and salt, but an ambitious philosophy backed up by sensible guidelines such as no cakes, biscuits, pastries or desserts to be provided except with lunch, and for free, fresh drinking water to be available at all times. The School Food Plan is the outcome of an independent review of school food commissioned by the Department for Education (DfE) and written by restaurateurs Henry Dimbleby and John Vincent. It aims to increase the take-up of school meals by improving food in schools. The plan sets out actions for head teachers so they can improve both the food on offer and how children learn about it. The DfE is also funding training in 5,000 schools that most need the help in making these improvements.

"Eating in school should be a pleasurable experience: time spent sharing good food with peers and teachers," the report begins. "These school food standards are intended to help children develop healthy eating habits and ensure that they get the energy and nutrition they need across the whole school day. It is just as important to cook food that looks good and tastes delicious; to talk to children about what is on offer and recommend dishes; to reduce queuing; and to serve the food in a pleasant environment where they can eat with their friends."

Pisani is readying herself for her next challenge with the School of Food and has trained up Chery-Lynn Booth, also a veteran of smart London restaurants, to take over at Gayhurst. "Getting children to try new food is half the battle," says Booth, who like Pisani has cut her hours in half by moving out of restaurants. "And you'll never get a kid away from their burger, but we use good-quality meat and put toppings out on the table so they can choose their own."

Both women say the job satisfaction here vastly outweighs any they've experienced before. "It's an amazing feeling when the kids walk in to get their food and they all say, 'Hi, chef!'" Booth says.

Two miles away, another Hackney primary, Mandeville, also has a new chef in the kitchen. Angela Church met Pisani through restaurant colleagues. She has a background in restaurants and private catering, and now uses her expertise to feed children well.

"My aim is to firstly feed them a balanced meal daily and secondly to foster an environment of excitement and joy around food and mealtimes," she says. Two of Church's staff are currently training in Gayhurst's kitchen, and the spot Pisani has found for her School of Food is over at Mandeville.

Jessica Vos was running food markets and planning to open her own restaurant when she heard about Pisani last year. She now serves a fully vegetarian menu at Greenside Primary in west London after the school decided to bring its catering in-house last autumn. "I make everything from Indonesian noodles to Mexican burritos, frittata, pasta, curries and pies," she says. "Everything is made from scratch, every day, and I try to use seasonal and local produce where possible.

"That special feeling you get when a child comes up to you and tells you they loved your food never gets old."

All the chefs report greater job satisfaction and are working far fewer hours. Their pay has been hit, but they get longer holidays. "When I started out cooking 20 years ago, I thought it would be amazing to teach kids to cook," Pisani says. "And now I am. Last year, I was getting really tired working so many hours, so it made sense for me to say yes to this, but now it's my dream."