Mix salt, sugar and freshly ground pepper in a bowl beforehand. Place the slices of fish that are cut into a container tightly to each other (but not overlapping, but just next to each other). As soon as you lay out one layer, sprinkle it with a mixture of salt, sugar and pepper and sprinkle with cognac. Next, also lay out the fish pieces in layers, sprinkling them and sprinkling with brandy.
Close the container with a lid and put the fish in the refrigerator for salting.
The salting time depends on how thinly you slice the fish. Slices 1 mm thick are salted, and slices 5-7 mm thick are salted for 5-8 hours. You can simplify storing fish in the refrigerator overnight or during the day.