Combine 1/2 cup sugar and cornstarch in a heavy
saucepan. Whisk together half-and-half and egg
yolks. Gradually whisk egg into sugar mixture;
bring to a boil over medium heat, whisking
constantly. Boil 1 minute; remove from heat.
Stir in butter, 1 cup coconut, and 1 teaspoon
vanilla. Place plastic wrap directly on pan to
cover and let stand for 30 minutes. Spoon
custard mixture into crust, cover and chill 30
minutes or until set.