Renowned for Armagnac and foie gras, this corner of southwestern France has a new claim to fame: Castelnau, a thirteenth-century village that has been transformed into a private retreat with 16 cottages for rent, each with its own kitchen garden.

As tourists, we tend to respond to two versions of luxury. One involves hushed service, marble halls and elaborate cooking—the costly bliss of grand hotels. The other has to do with space, light, and good, plain food, all in the middle of nowhere but (vital, this!) easily accessible. The second version, simplicity de luxe, is of course much harder to find; you have to know where to look. Now I do. Gascony.

Castelnau des Fieumarcon, in the southwest of France, land of foie gras and Armagnac, fits my criteria perfectly. It's just an hour away from the Toulouse airport; the international one at Bordeaux is nearby too. Yet within the stone walls of this privately owned thirteenth-century hilltop village, there are no cars or televisions, and even mobile phones are touch and go. The 16 cottages available for rent, which together accommodate 40-plus guests, are arranged mostly along two little streets. They are sensitively restored, and I find it easy to imagine life in these medieval dwellings, with their kitchen gardens and their doorways bordered with old roses and grapevines, six or seven hundred years ago.

The cottages are not, for the most part, luxurious, though one or two are grander—notably Cassagnet, which was once part of the old castle and has high, beamed ceilings and a huge salon complete with a grand piano. Little is left of the original castle beyond its gigantic stables (now listed as a historic monument), which house a new restaurant and will eventually include a library, an exhibition space and a concert hall. A shelf of land on the edge of the hill the town perches upon will hold an outdoor swimming pool, a steam room and a sauna.

But no jarring modern note obtrudes in my low-ceilinged cottage. My bed is a pretty, antique four-poster, and I hang my clothes in a wardrobe lined with cedar. An open log fire in the sitting room gives off a wonderful smell of lavender-scented woodsmoke; an urn of lavender-filled bags rests on the hearth.

Castelnau des Fieumarcon is the brainchild of Jean and Frédéric Calviac, who are also joint owners of France's largest organic-seed producer, La Ferme de Sainte-Marthe. The brothers love to restore old buildings: They just finished turning a historic Lisbon palace, the Palacio Belmonte, into a princely hotel with organic vegetables growing in its terraced gardens. Some years ago the two learned that the walled medieval section of their childhood haunt, the little village of Lagarde-Fimarcon, had been abandoned and the mayor wanted to bulldoze it. They decided to save it. Now they own every building within the thirteenth-century walls except the church.

Each of the 16 cottages has its own kitchen garden. Outside my door is a little vegetable plot no bigger than my bedroom, with emerald lettuces, radishes, leeks and heart-shaped coeur de boeuf tomatoes as big as a child's fist.

"Please help yourself," Jean says. "And before you go, plant some seeds so that future guests will also be able to pick fresh salads."

Some of Jean's guests don't want to cook, even though he keeps their refrigerators stocked with basic supplies (bread, butter, cheese, eggs and so on) and their kitchens equipped with up-to-date appliances. For these people—and I am one of them—Jean, like the good host he is, suggests the best local restaurants, a few within walking distance (just), or he cooks for us himself, either in our cottages or his own (larger) house, a few steps away. On major occasions, he can prepare meals for up to 100 people in the new restaurant.

One morning he recommends a good place to eat in La Romieu, about an hour's walk away, and offers to collect me in his car after I've had lunch there. La Romieu turns out to be another medieval hill town, sleepy and friendly. When I go farther afield, by car (hired at the Toulouse airport and parked just outside Castelnau's walls), I happen on more medieval hilltop towns: Lectoure, Fleurance, Terraube. All built more than 500 years ago for defensive purposes, they have dwindled now into little magnets for summer tourists.

If I ask, Jean will prepare me a picnic basket—cold roast chicken, tomato salad, melon—but once I sample his cooking, I'm too spoiled for such simple food. Instead I order from his informal menu and spend my sightseeing days looking forward to dinner. The first meal he cooks for me is a roasted guinea hen stuffed with plums and grapes and served with a chicken-liver pâté. The pâté is pale, rich and unctuous, its flavor sharpened by the tartness of the fruit. I sit beneath a bust of Molière in Jean's dining room, and at first my stomach can't quite believe the richness of the food."Why aren't you all fat in Gascony?" I gasp.

"We don't eat between meals," Jean says. "And we eat very little sugar."

On another evening, I feel like staying put in my cottage, so Jean brings food over and assembles a feast for me. He begins with a garlic soup so fresh and clean-tasting that it's like swallowing health by the spoonful. Then he takes a couple of minutes to concoct a perfect cheese omelet. To finish he serves me coffee and one of his walnut bars. This is true luxury, I decide as I stretch out beside the fire while slowly nibbling my dessert.

The trump card is that if you want you can have this walled village all to yourself. Castelnau would be the perfect setting for a big birthday, a wedding anniversary or any kind of special occasion: You would simply hire all 16 cottages for a few days and invite friends and family for a private party. An entire clan did that last Christmas, and for a few days the village played host to stepchildren, mothers-in-law, ex-husbands and third cousins twice removed.

But even if you were here with all your relatives, solitude would be easy to find. One morning I wake and open my cottage's shutters onto a blue sky and a hot early sun. A few minutes later I am out on the ramparts. On a two-hour walk I do not see a single person or car. When I stop to look at a flock of birds wheeling high up in the sky, I can hear their wings beating.

Castelnau des Fieumarcon is still in the process of being brought back to life, and it is a little rough around the edges. But some people—like me—will probably prefer this informal state of transition to the more polished finished product. For privacy, beauty and a sense of history, the village would be hard to beat as it is now. I am more than happy to sit in my cottage after my walk, with a slice of excellent local bread and Roquefort, a salad of vividly bitter leaves grown just outside the room and a glass of Buzet, gazing down the hill at a view straight out of a medieval Book of Hours.

London writer Helen Simpson is the author, most recently, of the short-story collection Getting a Life.