Combine 1/2 c. sugar and cornstarch in a heavy saucepan;
gradually whisk in half and half and egg yolks.
Bring to a boil over medium heat, whisking constantly; boil 1 min.
Remove mixture from heat.
Stir in butter, 1 c. flaked coconut, and 1 tsp. vanilla.
Cover tightly with plastic wrap, and cool to room temperature.
Spoon custard mixture into baked pastry shell, and chill 30 min. or until set.
Beat whipping cream at high speed with an electric mixer until foamy;
gradually add 1/4 c. sugar and remaining 1 tsp. vanilla,
beating until soft peaks form.
Spread or pipe whipped cream over pie.
Garnish, if desired. Yield: 1 9" pie.