Choose a heavy, low-sided container just large enough to hold the roast with a bit of space around—a small skillet or an enameled ironware gratin dish, for instance. Rub the liver liberally with olive oil, sprinkle it with salt, and put it into a 450° oven: Its specific treatment will depend on the quality of the oven; it should be seared at high heat, continue cooking at low heat, and relax at a temperature that permits it to remain hot, the heat contained within it continuing gently to penetrate to the heart of the roast. With my oven, which is extremely hermetic, holding heat for long periods of time, I start it out at from 450° to 475°, turning the oven off immediately and the roast is ready some 30 to 35 minutes later, the oven having gradually descended to about 200°. With friends’ ovens I have usually found the best method to be: (1) 8 to 10 minutes at about 450°; (2) another 10 minutes or so with the thermostat reduced to 275° to 300°; (3) 10 to 15 minutes with the oven turned off. It must, above all, not be left for too long a time at a searing temperature. Five minutes more than the time prescribed in a warm oven during the relaxing period will not harm it.
Transfer it to a heated platter and carve it at table, using a very sharp knife and slicing it as thinly as possible—no more than ¼-inch-thick slices, serving onto heated plates. A turn of the pepper grinder . . .