A Charentais devil is an unglazed earthenware pot used for dry cooking.
It is a low, flat pot with a small opening at the top, with a lid.
It is used for dry stove-top baking and roasting. No liquids are ever put in it, and it is never washed.
In times gone by, it would sit on a stand over the fire in the hearth.
Now, to use it on a stove top on an electric or gas element, you use a heat diffuser on top of the burner, and put the pot on top of that. You can also just put it in the oven, though that defeats the purpose of the pot.
A Charentais devil can be used to roast garlic, onions, or chestnuts in, or to bake potatoes in. Fans swear that the pot gives potatoes a taste as though they were baked in ashes in an old-fashioned hearth.
Scrub potatoes before putting them into bake. Very large potatoes may take up to an hour the on stove top. Shake the potatoes from time to time while they are baking in it.
When baking a head of garlic in one on the stove top, allow half an hour.