Preheat your oven to 350°F. In a mixing bowl, combine the graham cracker crumbs, granulated sugar, and melted unsalted butter until the mixture resembles wet sand. Press this mixture firmly into the bottom and up the sides of a 9-inch pie plate. Bake the crust for 8–10 minutes until lightly golden, then set it aside to cool completely.

For the lemon filling, whisk together the granulated sugar, cornstarch, all-purpose flour, and salt in a medium saucepan. Gradually add the water while whisking until smooth, then cook over medium heat, stirring constantly until the mixture thickens. Temper the lightly beaten egg yolks with a small amount of the hot mixture before returning everything to the pan. Continue cooking until the filling is thick and bubbly. Remove from heat and stir in the unsalted butter, finely grated lemon zest, and fresh lemon juice.

For the cream layer, beat the softened cream cheese with the powdered sugar and non-alcoholic vanilla in a large bowl until smooth and fluffy. Gently fold in the heavy whipping cream that has been whipped to stiff peaks.

To assemble the pie, pour the cooled lemon filling into the cooled crust, then spread the cream layer evenly on top. Refrigerate for at least 4 hours, preferably overnight, before serving.