Try the bacon ice cream

The Fat Duck in Bray is such a funny little place. It barely looks as though it's a restaurant, let alone one that has just been awarded three Michelin stars.

It's small and plain, and there's a tiny kitchen and a bar area and that's about it. Later on, when chef and proprietor Heston Blumenthal is feeding me caviar and white chocolate, he tells me that on an average night, there are 12 of them in the kitchen. Twelve! I say. It looks as though you can barely fit one. "Yes," says Blumenthal mournfully. "I have a horrible feeling things are going to have to change." The Michelin stars, he says, have really put him on the map. "I'm delighted, but now I look around and think, 'Does it look like a three-star restaurant?' The answer is no."

In a way, Heston Blumenthal likes change. In fact, as a 37-year-old self-taught chef who used to be a debt collector, he is the embodiment of the modernisation that is going on in the nation's eating habits. His tastes may be a little outré for most, but he's famous for dishes such as smoked bacon and egg ice cream, snail porridge, sweetbreads cooked in hay, salmon with liquorice, baked cod with braised cockscombs, and crab ice cream. He has spent the past year trying to find the ideal recipe for savoury candyfloss. He uses industrial instruments in his kitchen.

His favourite toy is a blowtorch. "I use this for crème br°lée and also for caramelising joints of meat."

His next favourite thing is liquid nitrogen. "Oh, nitrogen is amazing to cook with," he says. "Have you ever tried it?" Erm, no, I say. "You must!" he says. He then takes a bowl outside and sprays the freezing cold nitrogen in it. Plumes of gas stream up into the sky as Blumenthal chatters on excitedly. In fact, with his cropped hair and glasses he looks a bit professorial. He then takes the bowl inside, grabs a canister and out of that comes a spume of green gunk, a bit like a stiff mousse. "This is nitro green tea with lime." He then plunges the spoon into the liquid nitrogen, zooms the mousse around as if poaching an egg, scoops it out into his mouth and gulps it down like an oyster. "Delicious," he says. "Totally cleanses the palate." And then he starts the seemingly mad process all over again.

But, of course, Blumenthal is not mad. The bigwigs at Michelin do not give three stars to just anybody - he got his first in 2001, so his rise is meteoric. In fact, there are only two other places with three stars in the UK.

One is Gordon Ramsay's eponymous restaurant in London. The other is The Waterside Inn, also in Bray, whose proprietor is the famous Michel Roux. How does Bray, which is tiny, support two such marvellous restaurants? "What I do is completely different from Michel," says Blumenthal. "The Waterside Inn specialises in French formal cooking." Whereas the Fat Duck is small and relaxed - it's a Monday and it's closed but yet, for some reason, the door is open and people keep popping in and out as if it's the local shop. And the Fat Duck specialises in, well, what exactly? "Molecular gastronomy," says Blumenthal, "mixing tastes and textures and turning everything on its head."

There is something obsessive about Blumenthal. He was born in Shepherd's Bush - the Heston, he thinks, comes from a parental love of the service station, and the Blumenthal from a Latvian great-greatgrandfather - but grew up near Bray, in Marlow.

He didn't show any aptitude for cooking as a youngster and his parents weren't gourmets, either. His father, Stephen, ran an equipment leasing company. "My mother, Celia, was a good cook," he says, "but no more than that." His treat was to go to the Berni Inn and have duck à l'orange. But when he was 14 and on holiday his parents took him to a three-star restaurant in France. "We sat outside," he says, "and there was the sound of crickets and the smell of lavender and a huge cheese trolley, and I realised that that was what I wanted to do." He left school with one A-level in art and wrote to 30 restaurants asking for a job. Only Raymond Blanc at Le Manoir aux Quat' Saisons replied. "I topped and tailed beans for a week, and left," he says.

He knew then, as he knows now, that he was never going to follow a traditional style of cooking. For years he worked for his father as an accountant and debt collector to finance his dream of opening his own restaurant. But still he wouldn't bow to the bistro-culture, despite advice from friends who thought what he wanted to do was too left field and uncommercial.

"It's true that I have encountered bad feelings along the way," he says. "When I first opened here nine years ago people who came to eat thought I'd lost my mind. It was very home counties. I did steak frites and lemon sole. Gradually, though, I became obsessed with why we cook the way we do. Why do we boil greens in salted water to keep their colour? Why do we think putting meat in a hot oven seals the juices? I was always questioning, Why this? Why that? And no one seemed able to answer me."

In the end, Blumenthal found Professor Peter Barham at Bristol University. "I called him up and said, 'Do you really need salted boiling water for beans to stay green?'" and Peter said, 'Eureka! A chef who understands science!'" It turns out it's nothing to do with boiling or salt but the mineral make-up of the water.

"It's best to cook them at a low temperature in bottled water." He can also talk at great length about how searing does not seal in the meat juices at all and how, for most of us, our enjoyment of food is directly connected to how we're brought up. "We are all born with a blank canvas for our palates," he says. "Our tastes are formed by diet culture."

But this obsessiveness doesn't stop in the kitchen. He's mad about his health. He met his wife, Susanna, when he was 19, at their local gym. "We both still go," he says. "We're very into keeping fit." Susanna, it turns out, also has her own fair share of obsessiveness. "She runs the house," he says. "I am very busy and she has everything set up how she likes it. She's the one who cooks at home. I never do.

My children love her Sunday lunch." Susanna, apparently, tends to look after the children - Jack, 11, Jessie, eight, and Joy, six - herself. But, at the moment, although Blumenthal says she is very excited about the third Michelin star, she is currently having to be very tenacious about their son's education. "Jack, our eldest child, is dyspraxic," says Blumenthal.

"It is taking a lot of time to find the right place for him to go to senior school. Susanna's like a walking text book on the subject."

He says they first noticed there was something not quite 100 per cent with Jack when he was very young. "Dyspraxia is a form of autism," says Blumenthal, "and it seems to emerge physically in children. They would probably be described as 'clumsy'.

Susanna always thought there was something up with Jack but no one really listened to her. She went to see everyone and researched everything but people kept telling her he was 'going through a stage'. She refused to believe them and kept on and on until someone could find an explanation. We are both similar in that way. We like to know why and how and we refuse just to accept things people tell us."

At this point, of course, Blumenthal was starting up the Fat Duck on a shoestring. "There was myself and two mates in the kitchen," he says. "We had no idea if we'd get any customers. I'd hocked the house to finance buying the old pub that we transformed into the Fat Duck, and me and Susanna were living in a tiny rented cottage." How did his wife deal with it all? "She's always believed in me," he says. What? Even in the snail porridge? "Yep," he says.

"Of course it was hard. We didn't know if it would work and she was striving to get Jack diagnosed and we had virtually nothing but then she met a lady who said, "Oh yes, Jack's dyspraxic and that's not the end of the world" and people started writing about the restaurant and coming to eat here. Maybe it started out as a novelty at first but now I think people take it quite seriously and are more willing to try out the dishes."

And, of course, with all this came publicity. Restaurant critics - notably Matthew Fort of the Guardian and Matthew Norman of the Sunday Telegraph - love him. So much so that the Guardian offered him a column. "Yes, hmm," he says. "I love doing that column but it takes a lot of time." He's gone down well, apparently, but some readers have complained. I tell him I was going to do a pork recipe he suggested but balked when I realised I'd have to run my haunch of pig under a running cold water tap for 48 hours.

"Yes, I had a lot of complaints about that," he says. But he's not a cook, he's a chef, I say, and chefs are supposed to weave magic with food. If we could all cook like Heston Blumenthal - God forbid - we'd all be restaurateurs. He cheers up at that. "I'm stopping doing the recipes," he says. "I'm just going to write about food." I tell him I think that's wise.

Interestingly, though, Blumenthal rarely eats at his own restaurant. He often meets his friends, fellow chefs Marco Pierre White and Raymond Blanc, for lunch, but never at the Fat Duck. "I'm terrified of my own creations," he says, telling me he's about to serve me one of his favourite desserts. "I always tremble when I think about them."

But one day he decided to bring Susanna and all the children down for lunch. "We had the tasting menu," he says. "It's four hours long! I was so nervous it was ridiculous." Luckily, it was a success. "Jessie loved just about everything. Joy wouldn't eat the fish dishes and Jack didn't like the egg and bacon ice cream but wolfed down the rest." What did he and Susanna think of it? "We loved it," he says. "I had a weird moment when I felt proud. I never normally have the time to do that."

In a way, at the risk of sounding a killjoy, part of me wonders why he bothers. Surely he and Professor Barham are the only people who are genuinely concerned about whether green beans should be put in salted water or not? I mean, do we really need egg and bacon ice cream or chips cooked three times and injected with ketchup?

"I understand what you're saying," he says. "And the world may not need sweetbreads in hay but the thing is, this food delights me. It keeps me constantly interested in trying out new tastes and new formulas and that's why I never get stale."

And then, before I am supposed to go, he gives me a mango and lychee dessert with beetroot and Douglas fir accompanied by a small dollop of blackcurrant sorbet. "First of all you dip this vanilla pod into the pine sherbert," he says, motioning towards a small glass bowl filled with powdered sherbert mixed with essence of fir, "and then you take a mouthful of the rest." I follow his instructions. I dab the sherbert, which is very yummy. Then I pop some mango and beetroot and lychee and sorbet in my mouth and ... I am in dessert heaven. Eventually, once I have scoffed the lot, I tell him it is the most delicious thing I have ever tasted.

Heston Blumenthal smiles a big smile. "Maybe you'd like the snail porridge," he says delightedly, disappearing off towards the kitchen. I think we're in for a long afternoon.

The Fat Duck is at High Street, Bray, Berkshire (01628 580333).