Close-up: Allegra McEvedy

How to build a healthy eating empire? First, get expelled, then go to work for Robert De Niro

Allegra McEvedy is evidence that bad girls can come good. The one-time tearaway – expelled from St Paul's Girls' School, fired from her job at the Groucho Club – has just had her second cookbook published; serves healthy fast-food to 50,000 customers a week in the restaurant chain she founded; and received an MBE in October.

"It was an emotional day," says the 37-year old chef. "I got it for making good food affordable in a way that hasn't been done before. Neither of my parents are alive so there was a lot of looking up to the sky and thinking, 'I hope you can see this.'"

McEvedy's career has taken her from bossing a brigade of 50 men in Robert de Niro's Tribeca Grill in New York to opening the Carnaby Street branch of the award-winning Leon chain in 2004 with business partners John Vincent and Henry Dimbleby (son of David). "At catering college you're trained to think that Michelin stars are all that matters," says McEvedy. "But I had an epiphany when I was 25 and in the States: I want the best food to be available to the most people."

After a stint in San Francisco, where McEvedy cured her own prosciutto, she returned to the UK. She met her partner, Susi Smithers, while working at the ICA; they married in 2006 at a wedding catered by Heston Blumenthal. Other than food and Smithers, she has a real passion for travel: "My father was a psychiatrist by day and a historian by night. We travelled a lot and by the time I was 12 I had seen every outpost of the Roman empire."

Last year, McEvedy spent Christmas at work. "This year I'm giving my family more of me," she says. But they shouldn't expect a turkey. "I can't abide them. Instead I'll do a goose and a ham. And I'm baking an enormous pie. You've got to make Christmas fun."

'Leon: Ingredients and Recipes' by Allegra McEvedy (£20, Conran Octopus) is out now