PREPARE and bake single pie crust according to recipe directions, using a 9-inch pie plate; cool.
WHISK together sugar, milk, egg yolks, lemon juice, cornstarch and lemon peel in a medium, heavy saucepan. Heat over medium heat, stirring until mixture becomes thick. Remove from heat. Stir in butter. Cool at room temperature. When filling is cool, stir in sour cream.
POUR filling into baked pie crust, smoothing top evenly. Refrigerate at least 4 hours before serving. Garnish with whipped cream and lemon peel strips, if desired.
Serving Size (1 slice, 1/8 of pie), Calories 440 (Calories from Fat 220), Total Fat 25g (Saturated Fat 10g, Trans Fat 0g), Cholesterol 110mg, Sodium 220mg, Total Carbohydrate 50g (Dietary Fiber 1g, Sugars 28g), Protein 5g; Percent Daily Value*: Vitamin A 10%, Vitamin C 15%, Calcium 8%, Iron 8%.
*Percent Daily Values are based on a 2,000 calorie diet.