Preheat oven to 400°. On a lightly floured surface, roll dough to a 1/8-in.-thick circle; transfer to a 9-in. pie plate. Trim crust to 1/2 in. beyond rim of plate; flute edge., Line unpricked pastry with a double thickness of foil. Fill with pie weights, dried beans or uncooked rice. Bake 25 minutes. Remove foil and weights; bake until golden brown, 4-6 minutes longer. Cool on a wire rack., For filling, in a microwave, melt chocolate and butter; stir until smooth. Stir in vanilla. In a small heavy saucepan, mix sugar and cornstarch. Whisk in whole milk. Cook and stir over medium heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer. Remove from heat., In a small bowl, whisk a small amount of hot mixture into egg yolks; return all to pan, whisking constantly. Bring to a gentle boil; cook and stir 2 minutes. Remove from heat. Stir in chocolate mixture. Pour into crust., For topping, in a small saucepan, combine evaporated milk, sugar and butter. Cook and stir until butter is melted and mixture just comes to a boil. Remove from heat., In a small bowl, whisk a small amount of hot mixture into egg; return all to pan, whisking constantly. Bring to a gentle boil; cook and stir 2 minutes. Remove from heat. Stir in coconut and pecans. Pour over filling., Cool pie 30 minutes on a wire rack. Refrigerate, covered, until cold, at least 3 hours.