Combine sugar, flour, and salt. Whisk together to remove flour lumps.
Whisk or stir in milk and egg yolks.
Cook over medium heat, constantly stirring to prevent scorching.
Once the mixture has come to a boil and thickens, add vanilla, butter, and coconut.
Pour mixture into baked pie crust and top with meringue.
Sprinkle with coconut. Bake in 400° oven until brown.