It's my party, and I'll go where I want to

Mary Novakovich was dreading her 40th. The answer lay in inviting a bunch of friends to a 13th-century French mansion

Turning 40 can be a scary prospect for a woman, so I decided that the best way to take the sting out of it was to surround myself with friends and good food and wine. Not in any old restaurant, of course. That wouldn't be grand enough. No, a 10-bedroom mansion is a better idea, especially when it's in one of the officially designated "most beautiful villages in France".

Turning 40 can be a scary prospect for a woman, so I decided that the best way to take the sting out of it was to surround myself with friends and good food and wine. Not in any old restaurant, of course. That wouldn't be grand enough. No, a 10-bedroom mansion is a better idea, especially when it's in one of the officially designated "most beautiful villages in France".

The only problem was that I had never hosted a house party on this scale before. I knew the potential pitfalls: over-organising, fussing like a mother hen, not enough/far too much food. But I also knew the secret to hosting a house party: have everything in place for your friends and then leave them to get on with it. It's much easier if your birthday falls conveniently during warmer months, when lazing by the pool is uppermost in most people's minds. Choosing a location out of season, when much of rural France shuts up shop, requires careful thought.

Luckily, I found La Gandillone in the Tarn-et-Garonne region of south-west France. "My" mansion started life in the 13th century. Its vast, austere edifice of pale Quercy stone gives no clues to the wonders contained behind its blood-red gate. The first thing you see is the swimming pool - on a broad terracotta terrace with views over the rolling hills. To the right of the grand entrance hall is a cosy lounge lined with bookshelves, but to the left is the room that gives the house its "wow" factor. An enormous dining hall, with beamed ceilings, a huge open fireplace and a refectory table about 15 feet long. Now that's the place for a birthday dinner.

The astonishment continues as you lose your way round the house. The kitchen is big enough to hold a large dining table, and just off this is the billiards room. Then you have your choice of staircases leading to the 10 bedrooms, each with its own bathroom. We chose one of the two master bedrooms, naturally, with its own balcony and views over the hills. But the other guests didn't miss out, as all of the bedrooms were decorated to a high standard.

La Gandillone sits about 20 yards from the main square of Lauzerte, one of the loveliest of Tarn-et-Garonne's bastide villages. Like the other medieval "new towns" created during the Hundred Years' War, Lauzerte is perched on top of a hill, has an arcaded central square and, legend has it, secret tunnels connecting it to neighbouring hamlets.

All very charming and picturesque, but it did suffer from a lack of restaurants. Of the three cafés in the main Place des Cornières, only Le Puits du Jour was open. The square further down the hill, Faubourg d'Auriac, had two more cafés and restaurants, but French winter time had kicked in early. Little was open from Sunday afternoon till Tuesday morning. The Hotel du Quercy menu looked interesting, if expensive, but I was afraid that some of my friends would be put off by the inventive things the chef did with duck innards. That left Pizzeria l'Etna, which had a rather dreary interior. However, years of eating out in France taught me not to judge by outward appearances, and l'Etna served one of the best pizzas I've ever had. Shame it's open only four days a week.

All of this meant much more cooking at home than planned. That's when the calibre of guests becomes important. Invite people who can cook. My partner, who cooks considerably better than I do (gross understatement), oversaw the week's meals, but was happy to delegate responsibility when offers to take over poured in. My sister-in-law kicked him out of the kitchen one night, and my brother was master of the barbecue the next. Other friends took turns making starters and main courses and kept up the supply of alcohol, while a few were there purely for their entertainment value. (If you can't cook, you had better be amusing company.) Above all, don't forget to set up a kitty for the food and drink; only the most thoughtless wouldn't think of contributing, and you wouldn't invite them anyway.

Before the outset, one of my fears had been how to keep my guests entertained if the weather turned grim. We had brought a DVD player, a variety of films, board games and guidebooks to the region. As it turned out, the weather gods smiled on us that week. After a bitterly wet first night, the sun came out the next day, hung around for the whole week and raised the temperature to 24C (75F). Not bad for late October. The soft air and autumnal colours cast their spell and enhanced visits to nearby Montauban and Cahors (immediately dubbed "Chaos" by one confused friend).

Apart from one group trip to the Sunday market at Montcuq 10 minutes' drive away, everyone did their own thing. Some went riding at the equestrian centre just outside Lauzerte; others went to medieval Sarlat or the Parc Naturel Régional des Causses du Quercy. We had day trips to the prehistoric caves at Lascaux and to the extraordinary perched village of Rocamadour. Some were content just to potter around the village, wondering at the friendliness of the Lauzertins. (An out-of-season bonus, perhaps?) At about 5pm, people would drift back to the house, have a drink and tell us about their day. We'd still be on the terrace two hours later watching the sun set over the hills as the church bells tolled. The wonderfully mellow mood then turned towards one of merriment as the candles were lit and much food and drink were consumed in our baronial dining hall. Afterwards, some would watch a film while others chatted in the kitchen, or we would all get horribly drunk on Armagnac and sing along badly to Brian Wilson.

The only "wild" night was that of my birthday, of course. Then the party CDs came out and neighbouring villagers were treated to a group of drunk foreigners screeching along to Abba. Miraculously hangover-free the next day, we had just enough time to take in the lively Saturday morning market in the main square before we reluctantly packed and left "Mary's birthday house". It was a birthday I rather dreaded, but one I'll never forget.

GIVE ME THE FACTS

How to get there

The closest international airport to Tarn-et-Garonne is Toulouse, served from the UK by BMI (0870-6070 555; www.flybmi.co.uk) and easyJet (0871-750 0100; www.easyJet.com). For self-drive, cheap ferry crossings and hotel stopovers, go to www.drive-alive.com.

Where to stay

Bowhills (0845-634 2727; www.bowhills.co.uk) offers La Gandillone from £1,367 per week, including car ferry crossing.

Further information

French Government Tourist Office (09068 244123; www.franceguide.com).