Filled with anticipation, I held the black truffle to my nose and took a deep sniff. Nothing.

I sniffed again, straining to catch the rich earthy aroma I'd been told to expect. The truffle seller peered at me anxiously, seeing my disappointment.

"Wait a minute," he muttered, before shuffling around under the table and pulling out a grubby plastic bag.

"Those ones have been out in the air all morning, and their scent has dispersed."

He held the open bag towards us like an offer of gold: "Try this!"

Voila! The scent rolled out thickly like fine cigars or hot chocolate. At last, we smelt fresh truffle.

My husband and I have left behind the pohutukawa-clad coastlines of New Zealand to teach English in southwestern France.

We were drawn by the promise of an eternal summer, an exotic foreign culture and untasted gastronomic delights. So far, we have shivered through a bitingly cold winter that has conquered even my thickest thermal longjohns. But luckily the culture and cuisine have more than compensated for a few numb toes.

We began our education at the annual Truffle Festival in nearby Sarlat. This well-restored medieval village is found in the heart of Perigord Noir, an area known for its truffles, or black diamonds.

The day started at Sarlat's truffle market. I'd been expecting a large hall, filled with whiskery French farmers, conducting shifty deals in dark corners. After all, we had been warned of the craftiness of truffle sellers, who might fill holes in their precious produce with mud to increase their weight.

Instead, we found a tiny, cheerful room, filled with about seven truffle sellers and their wares.

This was actually a controlled market, where the truffles had been already weighed and categorised by experts. Our friendly seller told us how he'd found his truffles with his pet dog.

After a quick inspection - no mud - we chose a gobstopper-sized truffle for €9 ($18).

Curious, he inquired how we were going to eat it. "Perhaps an omelette?" we suggested. He nodded enthusiastically: "Now, you must put the truffle in a container with the eggs for about four or five days. This will infuse them with the truffle scent, even through their shells. Then cook your omelette, and add the truffle at the very end, so the taste of the truffle stays strong."

Advice dispensed, he gave us a cheerful wave, and wished us "Bon appetit!"

We moved to watch a competition between the chefs of Sarlat to create a tapas-type regional dish using truffles. Salivating at the selection, we jostled excitedly to get served.

We feasted on a crisp spring roll packed with juicy duck and truffle, truffle with orange cream sauce, and truffle with white fish and olives. An unpleasant marital dispute threatened when my husband forgot to share the next taster and swallowed his truffle-topped scallop whole.

It was time to move on. Loosening our belts, we explored the local market held inside a large gothic church. One vendor insisted we try all his walnuts - caramel, chocolate, icing sugar and, of course, chocolate walnuts flavoured with truffle juice.

We didn't need much convincing, and soon bought two bags. He then offered us slices of chocolate walnut brownie before handing us a small taster of white truffle wine.

As we left the market, we heard the loud speaker announce a truffle-hunting demonstration.

Outside the impressive Cathedrale Saint-Sacerdos, event organisers had hidden four truffles in a muddy garden for Chichi, a 2-year-old spaniel, to find.

The hunt began. Chichi darted away, then stopped and sniffed a nearby bush. The audience held its breath. Had he already found a truffle? Instead, to overall amusement, the dog crouched for a pee.

Business conducted, Chichi set off eagerly. Within 30 seconds, he was scratching at the base of a rock. His owner pushed him aside, and dug with a long spiked tool. Soon he held triumphantly aloft a grubby black truffle. Chichi was rewarded with a piece of cheese.

After lunch, we squeezed into the back row of another demonstration, this time by six chefs, five of whom had Michelin stars.

The first was Jean-Pierre Clement, from Maison Fauchon. The audience was silent as he created a celeriac coleslaw, adding port and truffle juice to his mayonnaise, and topping it with lobster and chopped truffle. As he plated about 40 tasters for the audience we looked resignedly at the rows of full seats in front of us. You can imagine our elation when the server announced he would start at the back.

The dish was creamy. Heavily scented with truffle, the flavour lingered on our tastebuds for hours.

We left the demonstration in time to explore the narrow streets of Sarlat with three troubadours in costume. The actors told a lively story of lost truffles, while educating their captivated audience in the history and sites of the village.

At the end of the day, the smell of truffles hung over the main square like a fog. But rather than being in gastronomic heaven, I felt like a child who'd eaten too many lollies. We brought home our truffle. It now sits forlornly in the corner of the kitchen in its lumpy plastic bag looking suspiciously like a small dog dropping.

The scent still torments me and I'm forced to enclose it in a second bag. Now, it's an anxious wait until my aversion wears off, so that I can finally savour my very own, black diamond.

CHECKLIST
Getting there: Cathay Pacific flies daily from Auckland to Paris via Hong Kong.

Perigord Noir Périgord Noir is in the Dordogne. It's easily accessed quickly via the national French autoroutes. Alternatively try the train from Bordeaux or Paris or look for cheap flights into nearby Bergerac from the UK (Ryanair and Flybe airlines).

Truffles: Truffle markets are held in December, January and February. While it's cold this time of year, visitors will be able to explore in peace, avoiding the crowds of English and French tourists who descend in the summertime.

What else to do: Explore its gentle valleys on foot, by horse, boat, canoe or bike. Visit the numerous chateaux and picturesque villages such as Beynac and La Roque-Gageac which nestle against craggy cliffs. The area is also home to many caves which feature prehistoric paintings (including the famous Grotte de Lascaux and its replica Lascaux II) or impressive natural stalactites and stalagmites.

Further information: The town has a website for visitors at perigordnoir.com.