Directions:

For the Crust:

In a medium bowl, combine the graham cracker crumbs and melted butter. Mix until well combined.
Press the mixture firmly into the bottom of a 9×9-inch baking pan. Place in the refrigerator to chill while preparing the filling.
For the Cheesecake Filling:

In a large bowl, beat the cream cheese until smooth. Gradually add the powdered sugar and mix until well combined.
Stir in the vanilla extract, lemon zest, and lemon juice.
Gently fold in the whipped cream until fully combined.
Spread the cheesecake filling over the chilled graham cracker crust and smooth the top with a spatula.
For the Lemon Topping:

In a medium saucepan, combine the lemon juice, water, granulated sugar, cornstarch, and lemon zest. Cook over medium heat, stirring constantly, until the mixture thickens and becomes translucent.
Remove from heat and let cool slightly before pouring over the cheesecake layer.
Chilling:

Refrigerate the assembled cheesecake bars for at least 4 hours, or until fully set.
Serving:

Before serving, garnish with whipped cream, lemon slices, and additional lemon zest if desired.
Cut into bars and serve.