1 (9 inch) baked pie shell
1/2 c. butter (for best flavor, DO NOT use margarine)
1 sq. melted chocolate
2 eggs
3/4 c. sugar
1 tsp. vanilla
2 c. Cool Whip, thawed

Using electric mixer, cream butter; gradually add sugar, creaming well. Blend in melted chocolate then vanilla. Add eggs, one at a time, beating 5 minutes after each with mixer. Fold in thawed Cool Whip. Turn into ready baked pie shell. Chill for 2 hours. DO NOT FREEZE.