Directions

In a medium saucepan, combine the sugar, cornstarch, and salt. Gradually stir in the water until smooth.
Cook over medium heat, stirring constantly, until the mixture thickens and begins to boil. Boil for 1 minute, then remove from heat.
Stir a small amount of the hot mixture into the beaten egg yolks, then return the egg mixture to the saucepan, stirring constantly.
Bring the mixture back to a gentle boil and cook for 2 more minutes, stirring constantly.
Remove from heat and stir in the butter, lemon juice, and lemon zest until smooth.
Pour the lemon filling into the pre-baked pie crust. Let it cool to room temperature, then refrigerate for at least 2 hours until set.
In a medium bowl, whip the heavy cream with the powdered sugar and vanilla extract until soft peaks form.

Spread the whipped cream over the chilled pie before serving.
Variations & Tips
For a meringue topping, you can use the leftover egg whites to make a meringue instead of whipped cream. Simply beat the egg whites with sugar until stiff peaks form and spread over the lemon filling before baking the pie briefly to brown the meringue. For a more intense lemon flavor, add a bit more lemon zest. You can also try adding a layer of fresh berries on top of the whipped cream for a fruity twist.