Melt chocolate and cool to room temperature. Cream butter and sugar until the sugar is totally dissolved and no grains remain. Add eggs one at a time and beat for 5 minutes PER egg. So, this means another 20 minutes of beating. Add chocolate, beat another 5 minutes. Add Vanilla, beat another 5 minutes. Pour into pie shell and top with whipped topping. Take a Hershey's Bar and a veggie peeler and shave the chocolate bar on top for decoration.