In a heavy saucepan, combine the salt, sugar and cornstarch together. Turn the heat to medium.
Slowly whisk in the half and half and cook until thick and bubbly.
Reduce heat and cook 2 minutes more, stirring constantly. Remove from heat.
In a medium-size bowl, whisk the eggs.
Whisk a bit of the hot half & half mixture into the eggs, a little at a time until about ¼ of the half & half mixture is mixed with the eggs. Pour it all back into the saucepan with the hot half & half mixture and whisk well.
Bring the mixture back to a boil. Remove from heat.
Add the butter, vanilla, and coconut...stir well.
Pour the mixture into the crust and chill well. It will thicken as it cools.
If desired, top with whipped cream and toasted coconut.