In a saucepan, combine sugar, flour, and salt. Gradually add milk, stirring until smooth.
Cook over medium heat, stirring constantly, until mixture thickens and boils. Boil for 1 minute, then remove from heat.
Stir a small amount of the hot mixture into the beaten egg yolks, then return all to the saucepan. Cook for 2 more minutes, stirring constantly.
Remove from heat and stir in coconut and vanilla extract. Pour into the pre-baked pie crust.
Allow to cool, then refrigerate for at least 2 hours.
Before serving, top with whipped cream, powdered sugar, vanilla extract, and toasted coconut.