Remove the crust from thin slices of sandwich bread. They should be about 3 in. long, 2 in. wide and 1/8 in. thick. Put slices of mozzarella cheese in between slices of bread. Beat 2 eggs in a large plate, with a little salt. Put the sandwiches to soak in the beaten egg, and leave them for about 30 minutes, turning them over once, so that both sides are saturated with the egg. Press the sides of the sandwiches firmly together so that the cheese is well enclosed. Fry them quickly in hot oil, and drain them on a piece of kitchen paper. Serve at once.