Prepare the Crust: Preheat oven to 375°F (190°C). Roll out the pie crust into a 9-inch pie pan, crimping the edges. Prick the bottom with a fork, brush with beaten egg white, and bake for 10-12 minutes until golden. Let cool completely.
Make the Cream Cheese Layer: In a bowl, beat cream cheese, powdered sugar, and vanilla until smooth. Gently fold in whipped cream. Spread evenly over the cooled crust.
Prepare the Lemon Filling: In a saucepan, whisk sugar and cornstarch. Gradually add water and cook over medium heat until thickened. Slowly whisk in egg yolks and cook for 1-2 minutes. Remove from heat, then stir in lemon juice, zest, and butter until smooth. Let cool slightly.
Assemble the Pie: Pour the lemon filling over the cream cheese layer, spreading evenly. Chill in the refrigerator for at least 4 hours or until set.
Add Topping & Serve: Before serving, spread or pipe whipped cream on top and garnish with lemon slices or zest. Enjoy!