1 deep dish pie shell
1 cup butter, room temperature
1 1/4 cup white sugar
4 ounces unsweetened chocolate, melted and cooled
1 TBSP vanilla
4 large eggs
1. In the bowl of an electric mixer, beat butter until light. Slowly beat in sugar until very light and fully blended. Stir in the thoroughly cooled chocolate, and vanilla extract.
2. With the mixer running, add the eggs one at a time, beating five minutes between each addition. It's truly important to beat the full five minutes after each egg.
3. Spoon the mixture into the prebaked pie shell, and chill for at least three hours before serving. Serve with whipped cream.