Heat the milk (don't boil) and pour over grated coconut. Let it stand for 20 - 30 minutes. Strain. Squeeze out the coconut cream and reserve. Discard the coconut. Combine a small amount of the coconut cream with sugar, cornstarch and salt. Stirring constantly, heat over low heat until scalded. When the consistency is smooth, pour into a 9" square cake pan. Chill. Cut into small squares.