Melt chocolate. Let cool. Cream butter; gradually add sugar, beating at
medium speed until light & fluffy. Stir in chocolate. Add eggs, one at a
time, beating 5 minutes after each addition. Fold in cool whip and spoon
mixture into pastry shell. Chill about 2 hours. Beat whipping cream until
foamy, gradually add powdered sugar, heating until soft peaks form. Spread
whipped cream on pie, garnish with chocolate.