Fit piecrust into a 9 in. pie plate. Fold edges under, and crimp the edge. Prick bottom and sides of crust with a fork. Brush some of the reserved egg whites over the surface of the crust before baking. (This will help to keep the pie crust crisp.) Bake according to the package directions for a one crust pie. If making toasted coconut garnish you can place the coconut on a baking sheet and toast in the oven while the pie crust is baking. Watch the coconut carefully or it can burn very quickly! (You may choose to blind bake the crust if you wish.) Allow the crust to cool completely after baking. 

Combine 1/2 C. sugar and 1/4 C. Cornstarch in a heavy saucepan.Whisk the Half & Half and the Egg Yolks into the dry mixture until smooth. Bring to a boil over medium heat, WHISKING CONSTANTLY FOR ONE MINUTE. Then remove from heat. Stir in Butter, 1 C. Coconut and 1 tsp Vanilla Extract. Cover surface of the pudding mixture with a sheet of plastic wrap and let stand for 30 minutes at room temperature. After 30 minutes, stir the coconut custard mixture and spread into the baked crust. Chill in refrigerator for at least 30 minutes or until set.

Beat whipping cream at HIGH speed with an electric mixer until foamy. Gradually add the 1/3 C. Sugar and the remaining 1 1/2 tsp. Vanilla Extract, beating until soft peaks form. Spread or pipe whipped cream over the chilled pie and sprinkle with toasted coconut if desired. Refrigerate until serving and store any leftovers in the refrigerator.