Bake pie shell at 425 for 12-15 minutes. Cool completely. Cream butter with sugar, stir in cooled melted unsweetened chocolate. Add one egg, beat at highspeed for 5 minutes. Add the other egg, beat for another 5 minutes. Fold in half the cool whip, pour into pie shell, top with remaining cool whip, shave curls of sweet chocolate on top with a potatoe peeler.