6 to 8
By Craig Claiborne
Combine the sugar and cornstarch in a saucepan. Add the butter, lemon juice, egg yolks, lemon rind and milk. Cook over medium heat, stirring constantly, until thickened and smooth. Chill.
Fold the sour cream into the chilled mixture and spoon into the baked pie shell. Chill well. Serve topped with whipped cream.