It is hard to believe Joanne Harris has chosen a restaurant with no chocolate on the menu. Before she arrives, I have time to spot a discreet Black Forest gateau lurking at the bottom of the menu – but that's your chocolate lot at Shrimpy's, a dashing pop-up in King's Cross by the canal. Mind you, it would be easy to understand if Harris were suffering chocolate fatigue. Her bestselling novel Chocolat (1999) has an unstoppable life of its own. It is published in 50 countries, was made into a film with Johnny Depp and Juliette Binoche, has had two sequels and has now led to The Little Book of Chocolat, in collaboration with Fran Warde – gorgeous recipes in celebration of the novel. On Twitter, her name is @joannechocolat.
She arrives wet, cold and smiling in a scarlet coat that stands out against the miserable weather. She sits down, tries to rub life back into her fingers and studies the menu with immediately likeable enthusiasm. She is dark with a pretty, quizzical face – and there is something comfortable about her presence, a soothing intelligence. She'd make a nicely updated Mrs Bun in Happy Families although not dressed for the part – she'd have to borrow an apron. She explains this restaurant suits her – she has a flat in the area. We go for crab burgers, a house speciality, and while she has chowder for starters, we address the chocolate question.
In the introduction to the recipe book, she claims her addiction is to cheese and chilli. "I'm not as sweet-toothed as people think." But cheese or chilli would never have been bestseller material? "I was told by a posh New York agent [pre-Chocolat] that no book with food in it as prominently as in Chocolat could ever be successful, that it was a silly idea. Now, I am loth to say anything is not going to work … because no one knows." Later, she explains: "I am often credited with having invented a genre – I'm not sure it is a genre. I certainly did not invent food in literature. Food is in Gilgamesh, fairytales, the Bible. In fairytale and folklore, it all comes back to cycles of feasting, fasting, magic and celebrations. Food is hardwired into some deep psychology of story." She salutes Angela Carter, Isabel Allende and John Lanchester for their work in the literary kitchen. Then she talks about a find in the British Library, a fantastical 14th-century recipe book by Geoffrey Fule that offers precise instructions on how to barbecue a unicorn.
Later, I notice, the fiction has more than one layer: Fule's recipes first came to light on 1 April.
The most influential chefs often turn out to be our mothers and Joanne's, an excellent cook, is French: "She was born in Vitré in Ille-et-Vilaine in Brittany, a medieval cobbled town with a castle." Her mother, she explains, has always had a strong belief that you can tell someone's personality by the way they eat. It is this simple: "People who eat well live well." Her mother, incidentally, is the translator of most of her books into French.
Her parents met when her father, a Yorkshireman, was in France, studying to become a French teacher. Her mother was studying philosophy but would eventually teach French too. That would make three: Joanne herself taught French for 15 years. She is bilingual and most "verbally outgoing" in French. Yet she sees an affinity between Yorkshire and Brittany: "They each have a strong regional identity and a reputation for forthrightness."
She tells the story of her father's initiation into his Breton family. "It was made very clear that a decision would be taken about his suitability as a husband on the basis of how he ate. His French was good but remember – this is a guy from the north of England who does not know about foreign food." Joanne's great grandmother, "a tiny, intimidating matriarch", was unsure about her favourite granddaughter's choice of spouse and prepared a banquet of endless courses and fancy wines. "At the end, when my father had staggered through repeated re-servings and thought he'd passed the test, my great grandmother disappeared into the kitchen and reappeared with an enormous stack of pancakes saying: 'I hope you have some room?'" He had no option but to eat on.
Celebratory pancakes featured throughout Joanne's childhood. Even now, when her daughter, Anouchka, returns from London (where she is doing an English degree) to Huddersfield where they all live, her mother's pancake pan is put back in service. But Joanne's mother was never a great believer in children eating sweets. She feared diabetes, the disease that killed her grandmother. This was ironic in that Joanne was born, in 1964, in a Barnsley sweetshop. "It was on the corner of a cobbled lane of terraced houses," she says. "It sold newspapers and had boiled sweets in glass jars. I don't remember eating many of them."
Joanne has given the psychology of food much thought. Three years ago, she tells me, she went to a slimming club and lost, in three months – on a diet of shakes and packet food – four and a half stone. She was the smallest woman in the group. She went anonymously and collected many stories about how "emotional eating shapes lives". "Many people use food as a displacement for other things which is why they are conflicted about it. They confuse food with intimacy, revert to food to articulate things they are unable to express in other ways."
After losing the weight, some women in the group discovered they were in the wrong job, some that they had married the wrong man. Others were "disturbed" to be seen, for the first time, as attractive. "They went back to their old habits because it was easier than being a different person."
The club was supposed to identify "eating triggers and avoid them … I'm well aware what mine are". And what are they? "Relief", she says, when something is over – a day's work. As a teacher, she barely ate during the day and "splurged" at night. She laughs: "Let's be frank here. My eating trigger is that I love food. I don't think I have any great emotional problems to eat my way out of which is why behavioural therapy does not work on me."
She revels in the changing attitudes to food in Britain. "We are at the forefront of adventurousness in cooking," she says, "it is a complete reversal." She glances back at her Yorkshire childhood, incredulously remembering that none of her schoolmates had even tasted pasta.
Our puddings have arrived. Unexpectedly, we chance on a shared secret: we once had a weakness for Yorkie bars. I say they seem gross now. She says: "I used to buy them secretly and consume them without telling anybody." And then she tells me about chocolates sent to her by fans, supporters of Vianne, Chocolat's heroine. Joanne says: "I think it quite normal to become fond of a fictional person." After all, you can get to know a fictional person better than anyone real. She tells me about a present inspired by another novel: "A large parcel with Arabic writing arrived at home. I found white powdery stuff inside and thought, 'Someone has sent me anthrax,' but it was coconut sweets powdered with sugar." It contained a "lovely letter" from a woman wanting to know whether her sweets were as good as Omi's, the Muslim woman in Peaches for Monsieur Le Curé. If not, she asked Joanne to send advice about what to add to "modify her recipe". Compliments do not come any sweeter. "It was adorable, they were excellent."
What would she nominate as her own favourite recipe? "I am very fond of hot chocolate, especially with cardamom." I tell her I will try it when I get home. I wait a day, then I do. It is sensational.
The Little Book of Chocolat by Joanne Harris and Fran Warde (Doubleday, £12.99) is out now
