You might have bumped into Yotam Ottolenghi at west Oxfordshire’s Wilderness Festival this summer, complete with a flowery crown.

“I stuck out like a sore thumb for days,” he laughs. “So the head-dress was the only way to fit in. It was so different when I went four years ago.”

The same can be said of Yotam himself. Having emerged as the new, definitive chef of the generation, he set about transforming our culinary landscape with his restaurants, delis and cook books, forcing us to share in a more communal, convivial, Middle Eastern way of life.

Gone was the meat and two veg of yesteryear, roasts now being embellished with vibrant, colourful salads full of ingredients we’d never heard of, Waitrose selling out of sumac and pomegranate seeds every time a new edition came out, proving Yotam to be more than a passing phase.

“The word ‘trend’ assumes a cursory element rather than the whole picture,” he agrees. “People talk about Italian food all the time, that’s not a phase, and neither is Lebanese. It has left its mark despite living in a fashion driven culture.”

Yotam has also since become a global phenomenon, spending his time flying around the world spreading the word.

Affable, chatty, and as considered as ever, our interview itself says as much about his love of Oxford as it does about the famous Jerusalem-born chef.

After all, Oxford was where he launched his last cookery book NOPI, named after his revered London restaurant, and where he sent head chef Ramael Scully to cook an Ottolenghi banquet at Hertford College. Yotam also accompanied Oxford Brookes Hospitality students to New Orleans courtesy of Oxford Gastronomica on a culinary tour.

Throw in his time at Wilderness and he’s a veritable local, which explains his upcoming signing and cookery demo at Waterstones in Oxford with latest offering Sweet.

And yet I never associate desserts and cakes with Yotam, his cookbooks being definitively savoury. “It was just the way the cookbooks panned out. So that was never the plan because the windows of all my delis are full of pastries and cakes.

“But we have been developing this for some time now and have regular cake meetings (with fellow author and friend Helen Goh) planned in my diary.”

Is that really a thing? “Oh yes. We’ll get together and test six to10 recipes and discuss how to improve them,” he says without a trace of irony, “because this is a massive book, bigger than any other, and we still had to narrow it down because there was so much to choose from. It’s been a two year project and we are very proud of it.”

“It feels like I’ve come full circle because I started off writing essays and then spent years in the kitchen and now I’m back to scribbling away at my desk every night,” he laughs.

Ah yes, the unrequited scholar, with a master’s degree in comparative literature from Tel Aviv University and a master’s degree in philosophy and comparative literature in Amsterdam, before moving to London for a six-month course at French cookery school, Le Cordon Bleu.

So does he miss the more academic life? “No, I’m happy because there is so much going on all the time and I’m constantly travelling and meeting new people and talking to chefs, so my work is always diverse and collaborative. That’s the only reason we have grown so exponentially. I designate. It’s the only way. I couldn’t do it on my own. There is only so much one man can create by himself.”

Plus, he has a lot on his plate these days (excuse the pun), his life changing irrevocably with the arrival of his two children Max and Flynn with husband Karl. Initially intensively private, Yotam later opened up about their ‘journey’ to have children, hoping to enlighten people about the process for gay couples.

“Having children changes your perspective, what you feel passionate about, what you eat, what you care about,” he admits.

So how does he balance his new family and his work? Do they travel with him? “No, they stay with Karl. He used to come with me of course but can’t now. I try to go away for the minimum amount of time because I miss them all so desperately.

“It’s not easy, but I need to travel for work and for inspiration. Because it’s a pressure to always come up with new ideas and new recipes. They have to come from somewhere (Ottolenghi has a Guardian column as well).

“Initially I just relied the food I grew up with, and ate as a child, but then I needed a greater variety - to embrace modern day cooking and international food.” Isn’t that sacrilege? “You can’t fight that and I think it’s important to adapt recipes while maintaining a few traditional classics.”

So does he despair of the conservative British palate? “British food is much more out there than elsewhere. You have a great food culture.

“But whether I do a book signing in Oxford or Seattle, everywhere I go people want to discuss the intricacies of the recipes with me and have proper food-driven conversations which is wonderful.”

Doesn’t he believe that people read his books then, despite the statistics?

“I am so surprised every time someone comes up to me and says I have changed the way they eat, and I’m over the moon about that. Because whatever the book sales figures, it’s hard to take on board.

“But food is such a joyful and life affirming experience and if I’ve contributed to that by opening peoples minds and larders, then, all the better.”

Yotam Ottolenghi and Helen Goh are in conversation with Sophie Grigson on Tuesday September 26 at St Aldate's Church, Oxford.