1 cup butter, softened
2 tablespoons sugar
4 teaspoons instant vanilla extract
1 1/2 cups confectioners' sugar
1 egg
In a medium bowl, cream together the softened butter, sugar and vanilla until smooth. Beat in the confectioners' sugar and egg. Pour mixture into the pie crust, filling to the top of the crust. Chill in refrigerator to chill, about 1 hour.