Heat the milk with the salt.
Sprinkle in the semolina and cook, stirring all the time, over a low heat until the grain is clear and the mixture thick — about 5 minutes.
Off the heat, stir in the sugar and egg yolks.
Allow to cool slightly.
Whisk the egg whites until stiff but not dry, then fold into the cool mixture.
Transfer to a greased pie dish and bake at 180°C/350°F/Gas Mark 4 for 30-40 minutes until lightly browned.