Soak the livers in advance for 10-12 hours in cold water, then drain and dry it thoroughly. With a sharp knife, cut off all the membranes.
Then place in an oven dish with the fat and cover it with thick greased paper. Bake in a hot oven (464°F (240 °C)), and every 2-3 minutes, pour on hot oil. After 10 minutes, add salt and leave it for 10 more in the oven.
Then remove, allow it to cool, and before serving remove the fat that covers it.