French Silk Chocolate Pie

1/2 cup butter, room temperature
3/4 cup white sugar
2 ( 1oz) squares, unsweetened baking chocolate, melted and cooled
1 tsp vanilla extract
2 eggs
1 prepared 8 inch pastry shell, baked and cooled

1. Cream butter in a mixing bowl. Gradually beat in he sugar with an electric mixer until light colored and well blended. Stir in the thoroughly cooled chocolate and vanilla extract. Add the eggs, one at a time, beating 5 minutes on medium speed after each addition. Spoon the chocolate filling into a cooled, baked pie shell.
2. Refrigerate at least 2 hours before serving