Preheat oven to 450°.
Line the pie crust with a double thickness of foil. Fill with pie weights, dried beans or uncooked rice. Bake 8 minutes or until bottom is lightly browned. Remove foil and weights; bake 5-7 minutes longer or until golden brown. Cool on a wire rack, set aside.
In a large saucepan whisk together the sugar and cornstarch. Gradually add the milk and lemon juice, still whisking until smooth. Turn the heat on to medium-high and continue to cook and stir until thickened and bubbly. Reduce the heat to low; continue to stir 2 minutes longer. Remove from heat.
Remove a 1/4 cup of the hot mixture and place in a small bowl with the lightly beaten eggs. Whisk together, then pour the egg mixture back into the pot. Bring the mixture to a gentle boil and cook for an additional 2 minutes. Remove from heat and stir in the lemon peel and butter.
Let cool (without stirring) on counter top for about 45 minutes. Stir in the sour cream, and pour into the pre made pie crust.
Chill completely in the fridge for at least 3 hours. Top with whip cream and enjoy!