2 (1 ounce) squares unsweetened baking chocolate, melted and cooled
1 teaspoon vanilla extract
1 prepared 8 inch pastry shell, baked and cooled
Cream butter in a mixing bowl. Gradually beat in the 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.