1Combine 1/3 cup sugar and cornstarch in a medium saucepan. Gradually add 1 1/2 cups milk, stirring well. Add chocolate and 1 tablespoon butter; cook over medium heat, stirring constantly, until chocolate and butter melt and the mixture thickens.
2Reduce heat, and cook 2 minutes, stirring constantly. Gradually stir about 1/4 of the hot mixture into 2 egg yolks. Add to the remaining hot mixture, stirring constantly. Cook over medium heat until the mixture thickens; cook an additional 2 minutes. Remove from heat, and stir in vanilla. Pour the chocolate mixture into the pie crust.
3Combine egg, 1/2 cup sugar, 1/4 cup butter, and evaporated milk in a saucepan. Cook over medium heat, stirring until mixture thickens. Remove from heat; add coconut and pecans, stirring well. Spread the coconut mixture over the filling. Let cool slightly. Cover and chill for 4 hours.