In a non-stick one quart saucepan, combine 3/4 cup sugar and 3/4 cup milk together. Bring the milk to boiling point and scald the milk. In a small mixing bowl, whisk the remaining milk, egg yolks, and cornstarch together. Whisk until smooth. Temper the egg yolk mixture into the scalded milk. Bring the mixture up to a boil and cook for about 3 minutes or until the mixture is thick, stirring constantly. Remove the pan from the heat and stir in the flaked coconut, vanilla and butter. Pour the filling into the prepared pie shell. Cover the pie with plastic wrap and place in the refrigerator. Chill the pie completely, about 2 hours. Using an electric mixture, whip the egg whites until stiff with the remaining sugar. Spread the meringue evenly over the top of the pie. Sprinkle the top with the toasted coconut. Place the pie in a pre-heated 350 degree oven and bake for about 8 to 10 minutes or until golden. Remove from the oven and cool.