Which would you tuck into: Milk Tray or truffles flavoured with chilli, taleggio cheese, olive oil, balsamic vinegar and Tuscan fennel pollen? Stuart Husband picks his way through the new 'jazz era' of hot chocolatiers proving that spice can provide the variety of life

Life is like a box of chocolates," Forrest Gump famously opined. "You never know what you're going to get." Gump was wrong (though admittedly he wasn't the brightest of bonbons). Not so long ago, you could untie the ribbon, fling aside the tissue paper, and dive into the selection box with a pretty good idea of what you were going to get: fruity crèmes and stoic nougats, with nothing more avant-garde than the occasional champagne truffle. More recently, however, chocolate has been getting more like life; more complex, more unpredictable and definitely more bittersweet.

A bunch of cutting-edge chocolate companies has sprung up, which are just as likely to combine their cocoas with herbs, spices, cheeses or even mild narcotics. They package their products like jewellery, hold regular tastings and talk of "gustative journeys". Quality Street this isn't.

One of the leaders in the field is Vosges, an American company run by Katrina Markoff. With her tousled hair, hello-trees-hello-truffles philosophy ("My mission is to bring peace to the world through chocolate," she purrs) and her "Free Yourself" cap-sleeve T-shirts, she's more rock chick than chocolatier. Vosges' products are described as haut chocolat - "art, fashion and chocolate in one" - and you'd look at the interior of its store in New York's SoHo, all mirrors and minimalism, for a long time before the phrase "pick'n'mix" came to mind.

"My life was totally changed by a fried chocolate truffle beignet I ate in the Place des Vosges in Paris," says Markoff, explaining the origins of her obsession. "I couldn't believe anything could be so beautiful. I was hooked, and the more I got into the taste of chocolate, the more I wanted to take it in new and unexpected directions," she continues, handing out samples of her Naga Bar (milk chocolate with curry powder, rich and unexpectedly sweet) and Red Fire Bar (dark chocolate with Mexican ancho and chipotle chilli peppers and cinnamon - as sharp and complex as you'd expect) by way of illustration. Markoff has taken the art/life interface further than most; her catalogue offers Indian yoga retreats to go with her Naga Bars, and silken robes in which you can lounge, in the style of Lady Cat from Tom and Jerry, sipping Vosges' Bianca white-chocolate drink with lemon myrtle and lavender flowers.

But Markoff met her match when she designed and named a collection in honour of the actor, artist, singer, director and downtown demi-god Vincent Gallo; a box of truffles containing Italian taleggio cheese, olive oil, balsamic vinegar and wild Tuscan fennel pollen. "A complicated collection that may not be understood by all palates," warns the catalogue, including, as it turned out, Gallo's; he threatened to sue for breach of copyright, and the collection was re-christened Rooster. "On reflection, something nutty and abrasive would have been more appropriate," says a chastened Markoff.

Other companies have enjoyed calmer collaborations. The London-based L'Artisan du Chocolat - "the Bentley of chocolate", according to Gordon Ramsay - has worked in its atelier with the chef of the triple Michelin-starred Fat Duck, Heston Blumenthal - he of smoky-bacon-and-egg ice cream fame - to produce a tobacco chocolate that yields caramel, coffee and vanilla flavours on first bite, only to be supplanted by a tobacco tickle on the throat. It's merely the most notable among a collection that also includes basil and lime; green cardamom; and marzipan and rosemary. "We're like chefs creating superb dishes," says L'Artisan's Gerard Coleman, "balancing the best cocoa beans with inventive flavours and exalting each of them. We're looking for that element of surprise."

Rococo, also based in London, aims to titillate too, with its organic bars in sea salt, black peppercorn and Earl Grey flavours, but owner Chantal Coady also emphasises the distinction between what she calls "real" and "fast" chocolate. The former is low in sugar, and cocoa solids from impeccably sourced beans form 50 to 70 per cent of the chocolate, while the latter can be as little as 5 per cent cocoa, with the rest made up of sugar, vegetable fats and artificial flavourings. "You don't need to gorge yourself on our chocolates," she stresses. "One hit is enough."

Montezuma operates from an old piggery in Sussex but its name acknowledges its loftier inspiration - the Mayans invented the chocolate drink in around 600BC, and the Aztec emperor Montezuma II would drink around 50 mugs a day, despite its mild laxative effect (hence "Montezuma's revenge"). "Chocolate was combined with herbs and spices from the very beginning," says Helen Pattinson, owner of Montezuma along with her husband Simon. "It was only when sugar came along that we got diverted down the sweet route. We're reverting, not innovating."

The Pattinsons left their high-flying City lawyer jobs and became enthused with chocolate during a stay on a Venezuela cocoa plantation while backpacking in South America; today they sell their Montezuma's Revenge truffles - with tequila, chilli and lime - through their shops in Brighton, Chichester and Windsor.

"It's a matter of educating the palate," says Helen. "People come in looking for Milk Tray, and they buy some chilli chocolate as a joke; it's also a leap of faith for people to spend £3 on a truffle. But then they find they really like it and they want more."

Would Alan Porter of the Chocolate Society be trying Markoff's cheesy concoction? "My first reaction is, yuk," he spits. "I think experimentation is fine, up to a point. It's a matter of taste, though I personally don't think herbs ever work with chocolate in the way spices do. The thing that worries me is that some people are using these strong flavours to mask the inferior quality of the cocoa they're using. We're going through a sort of freewheeling chocolate jazz age at the moment, but I think things will eventually come full circle. The basic top-quality dark chocolate will be around long after the star-anise truffle has bitten the dust."

For now, though, the jazzers are improvising furiously. "It's fun to play around in the lab and think outside the box," says Helen Pattinson. "We heard that Japanese flavourings - ginger, wasabi - are going to be the next big thing, so we're looking into those." A near-future in which the Terry's All Gold will be usurped in favour of the chocolate bento box? Perhaps, after all, Forrest Gump was a visionary.

For details and mail order: www.vosgeschocolate.com; www.artisanduchocolat.com; www.rococochocolates.com; www.montezumas.co.uk