Truffles are among the most valuable and sought-after of culinary delights.
For a Paengaroa couple, the air of mystery that surrounds the rare fungi has become a healthy obsession that is now a huge influence on their lives.
Colin and Maureen Binns began creating their truffiere - a grove of trees where truffles are cultivated - in 2008. In 2015 they harvested their first Black Périgord truffles.
Last year the truffiere produced around 3kg of truffles during the two-month season, which starts in June. This season, with the help of truffle dog Jed who sniffs them out, they have unearthed around 20kg.
Their half-hectare truffiere was treated with 70 tonnes of lime and planted with 212 oak and hazelnut trees ''infected'' with Black Perigord spores in October 2008.
The couple have continued to work on the area, to monitor all kinds of variables and increase their knowledge of growing truffles.
''For a hobby it's a) a huge investment, b) a huge risk, but c) it's a lot of fun,'' says Maureen.
Even internationally there are knowledge gaps in the cultivation of truffles. A harvest is by no means guaranteed - although this season, for one - they do seem to have got things right.
While the mystery surrounding successful truffle growth is part of the attraction, the uncertainty is also the reason, for the meantime at least, Colin and Maureen won't be getting rich from growing and selling truffles.
''We don't have a guaranteed supply to do that yet,'' says Maureen. ''There was no way in January, February and March we could have contacted chefs and said 'we are going to have heaps of truffles this year'. We just didn't know - until you dig, you don't know what you've got.
''And if you were doing it as a business, you would need more than a half hectare and you'd need to employ people.''
When Colin and Maureen moved to the property from Maketū, they set about transforming it.
''We love it, and grow almost all of our fruit and vegetables, plus we have sheep and chickens.''
Cultivating truffles was all about trying something different.
''They are elusive - what makes a truffle grow? We don't know. There are still varieties that people don't know how to grow and that you still have to go into the forest to collect - so there's an unknown and a wanting to know.''
As soon as it looked like this season was going to be a good one, Colin and Maureen began offering truffle hunts.
''This year we went through the first couple of weeks and we'd already lifted about 4 kilos and I said to Colin, 'oh my God what do we do?'
''Somebody suggested that because it's a real easy truffiere to go into and is relatively close to town, we should do truffle hunts.
''People have come from Auckland and Whangamatā, from Taupō and Tairua, we've had South African people, English people.''
Almost to a person, the visitors were unaware truffles could be grown in New Zealand.
''It's been really quite incredible and the response has been amazing - people stay and we have a really good time because we are sharing something that is really quite special, and the people who are coming are enjoying the experience are enjoying fresh truffles and enjoying finding a truffle.''
A self-confessed foodie, Maureen prepares a range of food using truffles.
''The flavour is amazing - it's an enhancement,'' she says. ''You can have bowl of plain pasta that's a bit bland, but really nice, and you are adding another level.''
She says while the flavour isn't for everyone, she doesn't find it overbearing or overpowering.
''Different truffles have different aromas - some are mushroomy and there are others that are caramelly.''
Colin and Maureen's growing fascination has also influenced their holidays and they have planned overseas trips around truffieres and truffles. The experience of a truffle hunt in Croatia is one that will stay in their memory.
''It gives you a purpose. We wouldn't have gone to the Istrian Peninsula in Croatia if we hadn't been doing a day on a truffle hunt and truffle tasting.
''You meet fabulous people because you have that same passion."
■ Celebrity chefs Kasey and Karena Bird from Maketū visited the truffiere before it had produced any truffles, and when they returned last week they were on hand to see Jed sniff out the largest find of the season so far - a 329g truffle.
Kasey says her idea would be to mix the flavours of truffles and paua in a pasta dish.
''I think the earthy seafood flavour would go really well with truffle,'' she says.
Karena would keep things very simple, adding truffle to potato puree.
''I wouldn't want to over-complicate things,'' she says.
• Black truffle or Périgord truffle is a species of truffle native to Southern Europe.
• It is one of the most expensive edible mushrooms in the world.
• Truffles are the fruiting body of a fungus.
• Périgord truffles grow from spores that live underground in a symbiotic relationship with the roots of certain tree species
• The fungus helps the tree extract nutrients from the ground and the tree provides the truffle fungus with carbohydrates to grow.