Take six good-sized, well-cleansed potatoes; with a round vegetable-spoon cut out the Parisian potatoes; then put them in fresh water; wash well, and drain. Melt an ounce of butter in a sautoire, throw in the potatoes, and season with half a pinch of salt. Place the sautoire in the oven; cook for twenty minutes, and serve on a hot dish with a folded napkin.