Taste of Home recipe card sent in by Erlene Cornelius of Spring City, Tennessee. This is a delicious recipe! I made fresh whipped cream to dollop on top of the tart but you can use Cool Whip or Dream Whip. I just prefer the taste of freshly whipped cream.
In a saucepan, combine the sugar and cornstarch. Gradually add milk until smooth. Cook and stir over medium-high heat until thickened. Reduce heat; cook and stir two minutes longer. Remove from the heat. Stir a small amount of hot liquid into egg yolks; return all to the pan. Bring to a gentle boil, stirring constantly. Cook two minutes longer (mixture will be very thick).
Remove from the heat, stir in butter and lemon peel. Gently stir in the lemon juice. Cover and cool completely.Fold in sour cream. Pour into pastry shell. Refrigerate at least 2 hours before cutting. Garnish with whipped topping.
Whip cold heavy whipping cream and confectioners sugar until thickened and stiff peaks form. Since everyone's sweet tooth is different, I would gradually add confectioners sugar until I received the desired sweetness.