Preheat oven at 200° C.
1. To prepare the salt crust, combine the flour with the salt and the egg whites. Use 6 whites if the eggs are large, more if they are smaller. The mixture should be thick and manageable.
2. Encase the fish in the salt dough and place on greased paper in a baking pan.
3. Cook the fish for 25 minutes. The crust should have become very hard and perhaps have taken a little colour.
4. Serve with the crust and break it at the table.
5. Horizontally slice open the salt crust, making sure not to damage the fish. Remove the fish carefully and place on a platter.