Chocolate Silk Pie

½ cup butter, softened
¾ cup granulated sugar
2 (1-ounce) squares unsweetened chocolate, melted
1 teaspoon vanilla extract
2 eggs
1 Pet Ritz Graham Cracker Pie Crust Shell
Cool Whip

Beat butter until smooth and creamy. Gradually beat in sugar until fluffy. Blend in chocolate and vanilla extract. Beat in eggs, one at a time, beating 3 minutes after each addition. Spread filling in pie shell. Chill 2 hours or until firm. Spread cool whip over chilled filling. Serve chilled. Yield: One 9-inch pie.