1 c. sugar
3 1/2 tbsp. cornstarch
1 tbsp. lemon rind, grated
1/2 c. fresh lemon juice
3 egg yolks
1 c. milk
1/4 c. butter
1 c. sour cream
1 baked 9 inch pie shell
1 c. heavy whipping cream or Cool Whip

Combine sugar, cornstarch, lemon rind, juice, egg yolks and milk in heavy saucepan. Cook over medium heat until thick. Stir in butter and cool mixture to room temperature. Stir in sour cream and pour filling into pie shell. Cover with whipped cream or Cool Whip. Store in refrigerator.