I ate this pie a few years ago and it was delicious. This recipe is from my Aunt Sue. See the note at the bottom about how to make this pie dairy-free. The cook time is the time to chill, and the prep time is an estimate.
In a saucepan, combine 1 cup sugar and cornstarch; add milk, egg yolks, butter or margarine, and 1 tablespoon lemon peel. Cook and stir over medium heat until thickened and bubbly; cook and stir 2 minutes more. Remove from heat; stir in lemon juice.
Transfer to a bowl; cover surface with plastic wrap and refrigerate until cool.
When cool, stir sour cream and blueberries into mixture; pour into pastry shell.
Cover and chill at least 4 hours.
If desired, stir a little lemon peel into sweetened whipped cream. Pipe or spoon atop pie. Garnish with lemon slices, if desired.
NOTE: If you use soy milk, dairy-free margarine, soy sour cream, and Cool Whip in place of the whipped cream this can be dairy-free.