Amanda Newton is a cook with a smile. She has good reason to grin: her work helps to encourage healthy eating among the young and old, while her kitchen is in one of the most beautiful parts of the country, in one of the UK's most sustainable buildings.

Amanda is head cook at the Brancaster Millennium Activity Centre, a National Trust-run environmental education centre on the expansive north Norfolk coast, an area increasingly embracing locally produced food. Housed in a charming converted 17th century dial house at Brancaster Staithe harbour, the centre prides itself on its use of renewable energy technologies and sustainable materials. The paint on the walls is water-based, the lino on the floor degradable; look twice at the attractive artwork and you will see that the shimmering mobile by the window is made from waste tin cans and the rag rug hangings are woven from unwanted jeans and tea towels.

Behind the scenes, a state-of-the-art heat-exchanger draws warmth from beneath the nearby mudflats to partially power the building and further renewable energy is supplied by sensitively hidden roof solar panels and a small wind turbine. Yet although visiting schoolchildren are encouraged to weigh their landfill waste at the end of each meal, the centre doesn't take itself too earnestly and delivers its environmental messages with a spoonful of fun.

Later this month, the regular weekly invasion of outward-bound schoolchildren will be replaced for the first time by adult organic food enthusiasts looking to pick up ideas for a Christmas feast. During the weekend retreat, Amanda will be demonstrating a range of locally sourced dishes and snacks, with not an intensively reared turkey in sight. On arrival, participants will be treated to a ready-cooked fish meal using ingredients caught metres away and landed at the Fish Sheds across the road.

The waterways surrounding Brancaster have been classified Grade B by the Environment Agency - the second cleanest grade there is and about as unpolluted as you're likely to find around the British Isles. As the National Trust owns 1600 hectares of surrounding creeks, saltmarsh and foreshore, a peaceful environment is guaranteed. On the Saturday, Amanda's apprentices will make snacks such as pies, flans and cheese tartlets and a dinner of local game, before visiting the nearby Courtyard organic farm, which supplies the centre with all its organic meat. Other dishes on the menu will be roast beef and traditional Norfolk treacle tart.

I dropped in to Courtyard Farm last month while enjoying a bite-size taster of Amanda's Christmas course, and found it, well, food for thought. The 900 acres of land, roughly half under grass and half under arable, have been Soil Association-approved organic for over five years, and are home to a pedigree herd of East Anglian Red Poll cattle, 40 Saddleback sows and 150 head of lamb. Wildlife strips teeming with life border the fields, while public access footpaths crisscross the land.

One condition of organic meat production I had been unaware of is that organically reared animals cannot have sight of other animals 'ahead of them in the queue' at an abattoir. Thankfully, the very happy pigs at Courtyard Farm have less distance to travel than most farmed livestock, as there is an organic-approved abattoir just 20 minutes away in the trailer. This means both minimum stress for the animals and better quality meat for the Brancaster centre.

According to farm manager Robert Giles local people are becoming a lot more interested in the taste, quality and the story of the food they eat, rather than simply heading for the nearest Tesco. "People will pay for the quality," he says. And pay for it they certainly do: the delicious steaks and chops his farm produces are only sold at the farm shop and selected local outlets, and can cost up to three times as much as their supermarket counterparts.

Although the on-site farm shop is only open for a few hours on Wednesday afternoons, sales now total £75,000 a year, including bulk orders from kitchens such as Amanda's. And a flick through local magazine the Eco Echo reveals plenty of organic and holistic events and suppliers springing up across East Anglia. Take your pick from an ear-candling conference in Norwich to an organic hair salon in Diss. By contrast, the Brancaster Centre has a firm footing in the mainstream as it seeks to bring the organic food philosophy into everyday life and take its mission to provide learning for all seriously.

Back in the kitchen, it's time for a demonstration of Mrs Temple's Binham Blue cheese tartlets, one of the dishes on the Christmas entertaining menu. Amanda barely pays any attention to what her hands are doing as they, seemingly autonomously, whip up the mix and fill the pastry shells. She has the air of someone who has been cooking so long it is as natural as breathing. Several imperceptible minutes later a plate full of irresistible golden pastries are filling the room with their deep, rich aroma.

With 30 years experience in the kitchen, including managing her own pub, Amanda is used to feeding 50 fussy schoolchildren a healthy lunch after their active morning of canoeing, orienteering, sailing or cycling. So the adults' Christmas cookery course should be a walk in the park for her. And with plenty of opportunities for participants to buy personal supplies of organic meat, vegetables and local fresh fish, the weekend is sure to sustain even the healthiest of appetites.

Way to go
A Festive Taste of Norfolk, Amanda Newton's pre-Christmas cookery weekend runs from November 24-26 and costs £190 per course participant, inclusive of twin bunk-style accommodation, tuition, ingredients, meals, refreshments and transport for offsite visits to organic farms. Accompanying non-participants are charged £110 inclusive of meals and accommodation. Call 01485 210 719 or email brancaster@nationaltrust.org.uk to book a place.

Further information
The Brancaster Millennium Activity centre offers a variety of adult residential courses throughout the year including birdwatching, cookery, painting and textiles. For more information see www.nationaltrust.org.uk/brancaster, call 01485 210 719 or email brancaster@nationaltrust.org.uk.

For more information on National Trust activities and holidays in the east of England visit the National Trust.

· Liane Katz stayed at The Victoria, Park Road, Holkham, Norfolk (www.victoriaatholkham.co.uk; 01328 711008). A double room costs from £115 from Sunday to Thursday and £370 for a weekend package. Single-night stays are not permitted on Fridays and Saturdays. Prices include breakfast.